PsychPortAudio Windows XP - duration issue...

Hello, everybody!
Trying to send auditory stimuli with PsychPortAudio we encountered a problem that apparently is not due to the script. We have a block of audio that is supposed to last 2 min (120 sec). When we run the MATLAB code on the MAC it works fine but on the Window XP the blocks are always shorter, i.e. they last half of the time they should (like 1 min instead of 2 min, 5 sec instead of 10 sec). We tried multiple times... 

Any clue about the problem?

Thanks!

Bianca,

from Neurospin, CEA-Saclay, Paris