I had a problem similar to this when i first used TT and my Rikaline 6010 mouse.
I literally took about a day to get anything and it was very unstable. I checked the signal strength via the GPS page in TT and found that the signals were almost non-exisitant. I tried all the options (changed make of GPS reciever in TT, moving to the open, reinstalling the GPS, screaming out loud...) and in the end gave in and returned the mouse for a replacement. The supplier was great and I got a new 6010 that week and it worked fine - lock is usually 1 - 2 mins and no roblems since.