Admittedly I have set the IE cache folders to a place other than the default, I have my own folder structure for caches on my CF card. I don't see how that would cause the problem though. It persists even after completely clearing the cache.
As far as I know I have the latest version... Just checked the file version you listed and it is correct, for bonus points the time of modification is 13:07:18 on 28/02/06.

I just re-downloaded the original package and the cab file for wm5 is the same size as the file I installed from last.
After I copied the file over I did do a soft reset so it used the used the new file, if necessary.
I don't want to cause you problems, I love the program as is and don't want to make you work on it just for me. I know just how much work is involved in this kind of thing, especially as you have no way to test it easily. Tell you what, call me a nutcase and we'll both pretend I was never here
Thanks for writing this great piece of software, it really is the best.