It seems to work perfectly here. It may be that the limb on your object isn't centered correctly (it's 0,0,0 isn't in the center of your object). Could you post a small example of how you are trying to do this. You need to post the code (and media if you don't use DBP made object like I did).
sync on: sync rate 0
autocam off : hide mouse
position camera 0,20,-50
point camera 0,0,0
make object cube 1, 10
make mesh from object 1, 1
delete object 1
make object box 1, 10, 10, 30
add limb 1, 1, 1
delete mesh 1
offset limb 1, 1, 0,10,15
do
rotate limb 1, 1, limb angle x(1,1), limb angle y(1,1)+.1, limb angle z(1,1)
sync
loop