Render to disk problem

[Scube]

I have one 21 bars lenght track. When I do a "render to disk" the result is always a 17 bars lenght track. It's really strange, I set the lenght to 20 and the loop point in the sample display is set to 21 (lenght = 20) The situation doesn't change in arrangement: here Live! tells me "Live will render the output of the chosen track over the selected time range. (1.1.1 - 21.1.1)". The result? a 17 bar lenght track!. I use Live since the version 3 and I'm using the procedures I always used. Pls help me..

Thanks
Scube