Why can't my iPod Touch 3rd Gen connect to my home WiFi?

Recently, my iTouch has been having problems connecting to my wireless internet. I would enter the pword and connect to the network, but I'm unable to go online or into the iTunes store. An error would pop out saying: Unable to Connect to iTunes Store: Invalid Argument. When I go look at the information for the network I'm connected to on my iTouch, it shows the IP Address and the Subnet Mask, but everything below that, including Router, DNS, Search Domains, and Client ID are blank when they should also be filled. Is it my iTouch problem or my Router problem? My laptop using the same network works perfectly. If anyone could please help me with this issue, I would greatly appreciate it.