VirtualDub Error

[PsychoticSoul]

Sorry If I look stupid and this has been asked before. I'm not very good with codec knowledge and these programs.

VirtualDub now gives me the following error when I try to open some Avi files in it
"Couldn't locate decompressor format for 'H264' (unknown)
VirtualDUb requires a video for windows VFW compatible codec to decompress video. Direct show codecs, such as those used by windows media player, are not suitable"

I think the avi file is in x264.
Virtual dub still opens other avis fine. I don't know why H264 is the problem, I thought that was an MKV format codec.
The program was working fine until I reinstalled the Combined Community Codec Pack because Zoomplayer had for some reason stopped being able to play some MKV files(and I didnt like using VLC to play them), which I think happened sometime after I had used VirtualDub and Autogordian Knot successfully before. I hadnt been playing MKVS in Zplayer for a while so I didnt notice anything.
Prior to reinstalling the CCCP, autoGK was also giving me the error "Avisynth open failure: Trim: Cannot trim if there is no Video. (I:\agk_tmp_.avs, line 10)"
I hadnt done anything to my codecs to screw things up, and previous files I had shrunk using Avisynth were in the same I: / Location. I reinstalled it and nothing happened.
I don't want to reinstall Virtual Dub because I think It'll mess up the CCCP and screw up my MKV viewing. Also When I reinstalled the CCCP I got a message, I don't remember exactly, something about the presence of virutal mod that could screw up the codec, and if I wanted to delete it, which I didnt.

What Should I do?

Thnx.

[guns1inger]

a. All codec packs are bad.
b. Virtualdub is a small, standalone program that installs wholly into a single folder and cannot screw up your codecs.
c. That CCCP believes virtualdub can screw up it's codecs shows you how little the creators of codec packs know, and how stupid they are.