1. make sure you have the newest version of ULX.. I BELIEVE that Megiddo has made the working version into the release rather than the SVn now.. so that should make that easy..
2. Make sure you have not just ULX.. but ULib as well.. they are seperate addons but ULX REQUIRES ULib to work...
3. Make sure you actually own GarrysMod... Im not accusing you so dont freak out.. just something I thought when you said Hamichi.
If all 3 of these check out, try running ULX on a clean GMod.. what I mean by that is put all of the addons you've downloaded other than ULX and ULib into another folder so GMod doesnt load them. It is possible that something you have conflicts with ULX.