Divx in Win Movie Maker

Ok...

I had the original DVD maker installed from my Win7Pro64bit,
I could take a Divx file, which I perfer to convert my video files into,
and load it up and burn it on a DVD.
For some reason I cannot now, it gets to .07% and gives me an unregonized error code, that is what it says.. and it stops.
I tried installing the new windows movie maker, as it is now called, and I cant even load a divx file into it... it just shows yellow triangles with ! in them ..

what is going on?

SO an update,
still no luck getting my Divx to work.. in any damn program really.

I use Divx Pro, and there really no help.. what little help they give is Divx devices play the format, doesnt have to be a real DVD, as thier software doesnt make dvds as much as it copies the divx file to it, and to the root directory at that...

I have over 300 movies, I'd hate to have to buy yet another program to back them up with.
Not really wanting to convert to other format, as that will just loose quality.
I just want to be able to burn them to dvd's again, it's the only way I can keep up with the kids destorying them.

update again to make more sense of the programs i'm using..

Corel Video Studio, ends up making a 800mb divx file 5.6gb when you try to burn in, but atleast it reads it and works with it.
Windows Live Movie Maker - doesnt even load Divx.
Windows Movie Maker - Loads, errors out at 7% encoding to burn them.

anyone work with divx files?
It would be nice if thier divx site was a site, but it's been in construction on thier forms for like, I onno, since they invented it..