Play movies over network

Hi All,
I’ve a problem with playing movies over network.
Briefly about my home network:
I run debian on Nlsu2 with connected usb HDD as a file server with samba. It’s connected via cable to switch.
I run XP and Ubuntu on desktop PC, also connected via cable.
I run XP on one laptop and ubuntu on other via wireless.
I struggle with it for a weeks now, I’ve done a lot of tests and changes and none of them seems to work.

When I play movie on XP laptop it skips all the time (every second or so), it’s fine on Ubuntu laptop and on desktop pc. Tests shows transfer on a large file around 600-800 KB/s (depends on where laptop is). So it’s fast enough to play it.
It’s same story with HD movies, when i try to play them on a desktop PC. On XP they skip in exactly same way as normal movies on laptop, when I switch to Ubuntu it’s much better (all though they freez every minute (more less) for a fee seconds, but I recon it’s more codes/ player fault then network. Transfer rate is 3MB/s
Can anyone help me with this? I spent couple of weeks now on google trying to find a solution.