folder names changing

hi ,
i use thunderbird 1.5.0.7 in a USB drive.when ever i copy and paste it to the local PC at home i notice that after starting TB it has changed folder names i have created for specfic emails through email rules. this happens only for one folder only .that is my bluebottle folder and the folder is shown in something like 8g6ccs, which is very confusing.

what can i do.
my main motive is to have TB run on a USb abd also have a regular upadated copy of it in my PC. is this the correct way to do it or should we only copy profile folder.

regards
rameez