During Install process, the folder cache/themes was deleted, it is ok, but in tools page it asks to chmod it.
My mind is: is this a bug (as in the code you call explictly my_rmdir_recursive) or cache/themes folder is needed?
The cache/themes folder is used to store css files and such for the theme that someone is using so we don't have to get that all from the database each time the page loads.
hmmm oh snap. No wonder. That's weird, during my testing it didn't remove the themes folder explicitly. I'll look into that again.
Edit: ohhh its because I had the .svn folder in there and that caused it to stop deleting the themes folder.
Thank you for your bug report.
This bug has been fixed in our internal code repository. Please note that the problem will not be fixed here until these forums are updated.