explorer halts when editing in moinmoin

If I have an image in a page and I place the cursor just after the image and type any character the following message appears:

Stop running this script? A script on this page is causing internet explorer to run slowly. If it continues to run, your computer may become unresponsive.

This happens in explorer 7 but not firefox 3.0.4. It doesn't happen in the Demo page on this site with explorer.

Any ideas?

Thanks...Dennis