skipping in video playback (1 Viewer)

[TheFuzz]

TV-Server Version:
MediaPortal Version: 0.2.2
MediaPortal Skin: BlueTwo
Windows Version: xp sp2
CPU Type: AMD Athlon 64 X2 5200+
HDD: Samsung 500GB Spinpoint T166 SataII
Memory: DDR2 PC5200 1024MB
Motherboard: Asus M2A-VM HDMI
Motherboard Chipset: AMD 690G
Motherboard Bios: original
Video Card: Onboard Radeon X1250
Video Card Driver: 8.380.0.0
Sound Card: Onboard Realtek ALC883
Sound Card AC3: coaxial out
Sound Card Driver: 5.10.5377
1. TV Card:
1. TV Card Type:
1. TV Card Driver:
2. TV Card:
2. TV Card Type:
2. TV Card Driver:
3. TV Card:
3. TV Card Type:
3. TV Card Driver:
4. TV Card:
4. TV Card Type:
4. TV Card Driver:
MPEG2 Video Codec:
MPEG2 Audio Codec:
Satelite/CableTV Provider:
HTPC Case: Antech Fusion V2
Cooling: Boxed cpu cooler & 2x120mm case fans
Power Supply: Antec Standard
Remote:
TV: Panasonic 68cm
TV - HTPC Connection: Composite


I'm trying to set my HTPC one step at a time. I'm having problems with my tv card when playing back an avi with media player if i play it through my vga/lcd screen there are no problems. However if i play it through me tv a get skipping and missed frames.

Any ideas appreciated.

Thanks