This is a tad strange... From the WP>Theme menu, I cannot delete the themes I do not want to keep. The deletion process seems to be running properly except that when the page reloads, the theme is still present, despite the message in the top yellow area stating that it's been deleted successfully... I am logged in as the Administrator and I'm able to perform all other tasks across the WP Admin app...
If I tried to delete the folders from my FTP app; likewise, I am not allowed to delete those theme folders. Theme folders permission is 755, and even that I am not allowed to change... and I am still the administrator...
Weird... Any ideas?