Need Help working VirtualDub on Avast

[REDACTED]

I recently bought a refurbished computer, Windows 7 Home Edition (my old computer with XP died). I never had trouble editing videos with VirtualDub on my old computer Windows XP.
However, with the newer computer Windows 7 Home Edition, it won't let me edit video files in VirtualDub.
I am using VirtualDub 1.9.11
When I try to open the video file, the following message pops up:
VirtualDub error:
Couldn't locate decompressor for format 'H264' (unknown)

I tried opening another video file and got different message:
VirtualDub Error:
VirtualDub requires a Video for Windows (VFW) compatible
codec to decompress video. DirectShow codecs, such as
those used by Windows Media Player, are not suitable.

Can you help me?

[Pondus]

Why do you think this is avast related?
Why do you post this in the viruses and worms forum section?

[Eddy]

Download and install the missing codec.
Problem solved.

http://www.videolan.org/developers/x264.html

[REDACTED]

Thank you all for your replies.