Wrong size of AVI in TAnimate

I have a strange problem...
If I drop a TAnimate component on a form and select aviFindComputer as CommonAVI property value,
the avi plays correctly on my NT box and on Win95 machines. But if I use this program on WinMe
or WinXP (I did not try on Win2000) the animation shown is very small. The stranger is that some
other avi do not do that, for example aviCopyFiles is correct.
Any clues?