Already using codec

[atocp]

Winamp 5.24 several clean installs
AMD Athlon(tm) 64 Processor 3500+, MMX, 3DNow, ~2.2GHz
Asus A8N SLI-Premium (Phoenix - AwardBIOS v6.00PG)
1024mb Mem
nVidia GeForce 6600GT 256mb with 6.14.0010.8198 (English)
Onboard AC'97 Sound
DirectX 9.0c (4.09.0000.0904)
Windows XP Professional SP2


The problem: Has been with Winamp for several versions, but not bothered me till recently. When using winamp to view AVI video files, I can only use winamp on its own, if i don't, i cannot have winamp opened second...e.g.:
If i want to watch 1 video i can open in winamp...If i want to open 2 video files at the same time (video editing purposes) i have to open winamp first, then open Windows Media Player or WMClassic second. If i open winamp second the video then flickers. When the video flickers in winamp, i can click and hold the bottom right resize corner and the flickering stops, but i have to keep holding. I think it is to do with the codecs being used. I am runing K-Lite MEGA codec pack, which i don't know if it is considered a 3rd party plugin (didn't think so) but winamp doesn't seem to be able to use a codec that is already in use. Even if NeroVision Express is using the codec for encoding one file, winamp cannot play another different AVI file at the same time. However, WMP, WMPClassic and others seem to be able to. I have tried several different options settings and clean installs but nothing seems to work, and as this has been around for a few versions now, i believe it to be a slight bug. If i am wrong please let me know and i will remove the post, but a fix would be very much appreciated.

Also, when opening a video file in winamp second, sometimes it is alright, but as soon as full screen is enabled in winamp (simply by double clicking the video) the flickering starts up.

Cheers,
ATOCP