I think you'll have to rename the file.

http://support.microsoft.com/kb/202261
You cannot use a pound character in a file name for a hyperlink in an Office
program

Excel Curious wrote:

I'm trying to add a hyperlink in excel to a pdf document that has a "#" in
the title such as 2359, #0006.pdf

I've tried replacing the "#" with %23, which was suggested to me, but does
not seem to work.

--

Dave Peterson