i tried to use redbox too and as you say it works fine on firefox, however on ie7 I do get the redbox but it is squished over to the right edge of the window, and is transparent.
so basically unusable.
There are a number of patches mentioned in the comments on this blog, but none seemed to fix my problems, YMMV
http://blog.craigambrose.com/past/2006/9/22/redbox-release-2/