When I try to use some of the themes (e.g. Excalibur) I get this message with a yellow exclamation mark triangle

Uninitialized Variable
Uninitialized Variable: Moduledir
at line: *Popup "module docs"
!PopupFolder:"$ModulesDir$docs\"
[ok]
It still loads but stuff doesnt work. I beleive that I am supposed to change msvcrt.dll to fix it but I can find no way s that always seems to be in use, I have tried many methos but any suggestions would be helpful.

that's because $ModulesDir$ is uninitialized ;)
if you check the step.rc then you can see that instead of ModulesDir there's ModDir. so you sould alter your popup or all the entries in step.rc, which contain ModDir.

And don't forget to tell the author to rename the evar, otherwise the theme is NOT OTS compliant.