There aren't too many things more frustrating than getting an error on the Wii. You might be about to score the winning goal in Strikers until the screen goes dark and reads, "ERROR CODE: 32002". Or you might be hoping to do battle over PBR with some friends, only to find Error Code 52230 blocking you.
Support.nintendo.com has
a pretty valuable search tool that lets you find the reasoning behind these cryptic codes. This thread is meant to consolidate and provide a shortcut to Nintendo's official answers to your error code woes.
Error codes can be five-digits or six-digits long, and some of them might be grouped to mean the same thing. I listed the error codes in numerical order and wrote all the numbers out (except for
Wii Error Code Group: 204800 through 205699, for fairly obvious reasons). So if you use Ctrl+F to search your specific error code, you'll jump right to the link you need to click.
This first part will consist only of the official solutions provided by Nintendo's customer support website. The second part will consist of more unofficial explanations (meaning they will include additional error codes, and additional explanations to error codes in this first part).
FIVE-DIGIT CODES
Wii Error Code: 32002
Summary: Poor connection due to wireless router channel or Nintendo's server.
Wii Error Code: 32003
Summary: Low internal memory space. Clear out some space or use a memory card.
Wii Error Code: 32004
Summary: No connection due to high traffic or incompatible connection.
Wii Error Code Group: 50420, 50421, 50422
Summary: Your Wii LAN Adapter has not been properly installed.
Wii Error Code Group: 51020, 51021, 51022
Summary: Specific troubleshooting required.
Wii Error Code: 51030
Summary: The only wireless network within range of your Wii console is not configured or is not compatible with the Wii.
Wii Error Code Group: 51031, 51032
Summary: The only wireless network within range of your Wii console is not configured or is not compatible with the Wii.
Wii Error Code Group: 51040, 51041, 51042
Summary: Troubleshooting for the Nintendo Wi-Fi USB Connector needed.
Wii Error Code: 51130
Summary: Check your router's broadcast settings to find out if it is set to "G", "B", or "Mixed." Mixed typically works best, but try all three to see if it improves the network connection to the Wii console.
Wii Error Code Group: 51330, 51331, 51332
Summary: The Wii console is not able to connect to the access point.
Wii Error Code Group: 51340, 51341, 51342
Summary: The Wii console is not able to connect to Nintendo Wi-Fi USB Connector.
Wii Error Code Group: 51420, 51421, 51422
Summary: The Wii console is not able to connect to your wired router or modem.
Wii Error Code Group: 52020, 52021, 52022
Summary: Connection difficulty with either router or modem.
Wii Error Code: 52030, 52031, 52032
Summary: Can be caused by using the wrong router channel or by having a WEP key. Simply power cycling the router may help.
Wii Error Code Group: 52040, 52041, 52042
Summary: The Wii console is not able to connect to Nintendo Wi-Fi USB Connector.
Wii Error Code Group: 52120, 52121, 52122
Summary: Power cycle your router/modem.
Wii Error Code Group: 52130, 52131, 52132
Summary: There appears to be an issue with your wireless router's firewall.
Wii Error Code Group: 52140, 52141, 52142
Summary: The Wii console is not able to connect to Nintendo Wi-Fi USB Connector.
Wii Error Code Group: 52220, 52221, 52222
Summary: There appears to be an issue with your router's firewall.
Wii Error Code Group: 52230, 52231, 52232
Summary: Your firewall is interfering with your Wii's connection.
Wii Error Code Group: 52240, 52241, 52242
Summary: This error code usually indicates that the Wii console was able to connect to the Nintendo Wi-Fi USB Connector, but is blocked from reaching the appropriate server(s).
Wii Error Code Group: 52420, 52421, 52422, 52430, 52431, 52432, 52440, 52441, 52442
Summary: The Wii console is not able to connect to your Proxy server.
Wii Error Code Group: 52520, 52521, 52522, 52530, 52531, 52532
Summary: The Wii console is not able to connect to your Proxy server because the account settings are incorrect (such as Username and Password).
Wii Error Code Group: 52540, 52541, 52542
Summary: The Wii console is not able to connect to a Proxy server because the account settings are incorrect (such as Username and Password).
SIX-DIGIT CODES
Wii Error Code: 109107
Summary: The WiiConnect24 service is being blocked by Parental Controls placed on the Wii console.
Wii Error Code: 109139
Summary: WiiConnect24 is not enabled.
Wii Error Code Group: 110210, 110211, 110212, 110213
Summary: General WiiConnect24 error. Call 1-800-255-3700 for help. (Search for your error code below for further explanations).
Wii Error Code: 204038
Summary: Wireless interference is blocking access to the Internet Channel.
Wii Error Code Group: 204800 through 205699
Summary: General Wii Shop errors. If you are receiving an error while attempting to purchase items on the Wii Shop Channel, you may want to use another credit card, or contact the credit card provider for the card that you were attempting to use.
Wii Error Code: 205906
Summary: There is a problem with your online account. You will need to call 1-800-255-3700 for help.
Wii Error Code Group: 205926, 205927, 205928
Summary: An error has occured that cannot be resolved at this time. Call 1-800-255-3700 for help.
Wii Error Code: 206401
Summary: Invalid My Nintendo username/password.
Wii Error Code: 206673
Summary: There is an issue with your Wii Shop account. You'll need to call 1-800-255-3700 for help.
Wii Error Code: 208000
Summary: You provided an improper county (Note - not count
ry) while attempting to download items from the Wii's online service.
Wii Error Code: 208001
Summary: You'll need to call 1-800-255-3700 for assistance if you live in US/Canada.
Wii Error Code: 208002
Summary: There is a problem with the billing address you provided.
Wii Error Code: 208003
Summary: The card number you provided is not consistent with the type of card you're using.
Wii Error Code: 208004
Summary: There is a problem with the Card Security Code that you provided.
Wii Error Code: 208005
Summary: There is a problem with either the card number or expiration date you provided.
Wii Error Code: 208006
Summary: The card number you provided is invalid.
Wii Error Code: 208007
Summary: The expiration date you provided is invalid.
Wii Error Code: 208008
Summary: The postal code you have entered is invalid.
Wii Error Code: 208009, 208010
Summary: "Processing your request".

Nintendo is experiencing server issues, so you have to wait a while before your card info can be validated.
Wii Error Code: 208011, 208012, 208013, 208015, 208017
Summary: Your credit card was declined.
Wii Error Code: 208014, 208016
Summary: Your credit card is expired.
Wii Error Code: 208018, 208019
Summary: The card number you have entered is invalid.
Wii Error Code: 209576
Summary: Connection timed out.
Wii Error Code Group: 209600, 209601
Summary: Likely connection time-out.
UNOFFICIAL SOLUTIONS TO CERTAIN ERROR CODES
These solutions come from secondary sources throughout the web, not necessarily from Nintendo. They might work, they might not. I'll list the sources of information that I used at the very end, for your convenience.
Error Code: 110213
This error won't interfere with normal offline gaming, but it will interfere with your ability to make updates and go online. The only way to get rid of this error is to have your console serviced by Nintendo. Click here for information on Wii repairs.
Error Code: 208019
Specifically, the zip/postal code that you entered may be incorrect. Double-check the info you put down, and if the problem persists you should contact your card issuer.
Error Code: 209593
May occur in the Wii Store if there is an invalid URL.
Error Code: 209826
Seems to occur when the Wii Shop Channel is left idle for too long.
Error Code: 220602
There appears to be an issue with your wireless router's firewall.
1. Try a Manual Setup with the Wii console, using your network's DNS information. To access the DNS settings: - On your PC, click "Start" and then "Run."Type "CMD" into the field that appears to open a new window.
- Type "IPCONFIG/ALL" and press "Enter" to display a list of internet settings, including the "DNS" settings. Input these into the "Manual Setup" of the Wii console's internet connection.
2. Review the information on our Firewall/Antivirus/Antispyware/Adware compatibility information by clicking here. This page offers many tips and recommendations to get your connection working through a firewall and other security programs that can be blocking the Wii console's online connection.
Sources
http://www.wiierror.com/errors.php
http://wii.ign.com/articles/746/746907p1.html
http://wiigoterrors.com/
http://www.errorforum.com