Actually, that might be the problem: since rada is not a native speaker he might be a Google Mail user from one of the several countries that are not allowed to use the word gmail because of trademark issues (Germany is one example).
If you are from one of these countries, you must enter your address as: your_username@googlemail.com (i.e. googlemail instead of gmail after the @ character)
Maybe that helps? This issue is much underdocumented both on Google’s part but also in the GTalk Adium settings. And it can make you go crazy