Can you play the IMM4 video at all? If not, get the codec from here:
http://www.cctvone.com/download/inde...%2F00A+Series/
Then get TMPGEnc free edition from here:
http://www.tmpgenc.net
(The download button is well-hidden at the very top of the page, between "about tmpgenc" and "forum" after you pick your language).
The process should be fairly intuitive from there.
If for some reason TMPGEnc can't read the AVI, the codec might be a DirectShow one. In that case, go to options, then click environmental settings, then on the vfapi plugin tab right click 'directshow multimedia file reader' and keep increasing the priority until it's the highest.