The Nintendo DS is unable to connect to an Access Point. What to do will depend on where you are connecting from:
Connecting from a wireless home network:
If you have multiple connection files saved to your Nintendo DS, the error message you received can help determine which connection file may be experiencing a problem:
Errors ending in 0 = connection file 1
Errors ending in 1 = connection file 2
Errors ending in 2 = connection file 3
Errors ending in 3 = Nintendo Wi-Fi USB Connector
Make sure that the DS is within 30 feet of the wireless access point and facing in its general direction.
Make sure that any other interfering devices, such as microwaves and cordless phones, are turned off.
I got this from Nintendo Support.