Usually the problem is an extra space or maybe there is an accented character in there - your generator is probably at fault. Try pasting to a text editor between two known visible characters and see what gets dumped there.

I have seen (PC) filenames get awkward characters usually after saving them from a Mac. Editing the name doesn't sovle the problem of reading the files either.

One annoyance is on one of my web pages. the hash code display and generator. Because the hash code is in a table cells and centered the is always one space in front of the code which isn't there when you highlight and copy. See code generator page and click on Euro Accents (for instance) - copy and paste the code above and a space appears. (Any browser)