Im trying to resize my .avi for a .gif

Ok, I got my .avi file but it's to big for a .gif I just want to capture the cat (which is only on the bottom left corner)

http://www.gifninja.com/Workspace/929acc27-13da-4e9a-8ba5-5379af617a26/output.gif

Anyone know a good free cropping .avi program?

 

Assuming you want to crop the AVI and save the frames as a sequence of image files (not as a video).
Load/drag the avi into VirtualDub.

'Video' > 'Filters' > 'Null Transform' and click on 'Cropping'.
Crop the image, then 'File' > 'Export' > 'Image Sequence'.
The images (perhaps hundreds of them) should be saved to a folder.
You can select bmp, jpg, png.

You could also save the cropped video to a new avi file, but note that some compressors expect the frame dimensions to be multiples of 4,8,16 etc.

 

Im getting an error: Invalid AVI file: The main 'movi' block is missing.

 

Try loading the file in AviDemux.
If it loads it ok, save it by clicking on the 'Save' logo or File > Save > Save Video..(give the new file a name including extension, e.g. new.avi)