Well I finally found out the problem!

    It has nothing to do directly with Csound, ouffff...

    It's a hard disk problem apparently. I think my external drive
didn't agree with rescaling stuff... although most of the time it works
well! So i tried my internal drive and everything went ok! (SCSI
problem? drive problem who knows??)
    Well thanks to everybody who helped out.
PS: the score is not a masterpiece, it's only a part from a part of an
additif stuff. And sorry for those who asked for the samples, i can't
send them first because i don't want to annoy everyone, 2) they are 3
mega each, and i have a slow line out here!
    Maybe next time, will send you something worth computing!

    Thanks again, and happy Csounding
    Karim