Render to Texture not working

When I try to Render to Texture nothing happens. I've tried all variations of settings. I can press "Save Image" or "Save all" and enter the file name but the files are never created on disk. Has this happened to anybody else? Thanks!

[EVOLVED]

Treeit might not have permission to write files to certain directories (such as the program files directory), try runing treeit.exe as an administrator allowing to overwrite these privileges.