Some devices can be very picky about things like the name of the wireless network. Printers, DVRs, etc come immediately to mind.
Make sure that the name of your wireless network meets the following guidelines:
1) Keep the network name short.....12-16 characters at most. Less would be better
2) Make sure that there are no special characters (like an apostrophe, asterisk, dollar sign, etc in the name of the wireless network
3) Make sure that there are no blank spaces in the wireless network name
So, for example there is very little chance that the cooker would ever connect to a network with a name like.....
GLaker33's Red Apple Wireless Network.
Use a wireless network name like GLakerWireless
Tesserax also has very good advice to temporarily disable the wireless security on the network if you are still having problems. After all, if the cooker cannot connect to a network with no wireless security, it will never connect when security is enabled.