Had a file on an FTP server that I was logged into, the filename was similar to
“c:\folder\filename.php” (i.e. the filename had c:\ in it)
I think this was a result of Uploadify, which has now been removed (more to come on that later). My FTP client wouldn’t let me delete this file as it contained invalid characters. Anyway, as a solution to delete the invalid file, pop this php code in a fixme.php file in the same directory as the dodgy filename:
Call that page and the the file will be removed. Sorted.