HTML Desktop Crash Help

Hi guys. I just joined, but I have to say this forum is great. I've managed quite a lot with all of your help, so maybe you can help me with a somewhat trivial (though annoying) problem I've been having.

I wrote an HTML file for my desktop which contains some Javascript and some use of ActiveX controls. Now, when I try to change my desktop from a bmp or jpeg to my HTML file, it seems that RunDLL32 crashes and Doctor Watson opens. The desktop properties window freezes, too, and closes when I end the doctor watson process.

Here's where it gets pretty weird: SO "Desktop Properties" crashed about ten times, and then out of curiosity I set the desktop to a blank HTML file. No crash. And now it doesn't crash when I use my much more complex web page.

I've had a similar experience after several formats, and it's really annoying - the crash always seems to go away eventually, but I'm not quite sure why. This is the first time I've tried using a blank HTML - other times it seems to have gone away for other reasons. What the heck is going on?