problems installing IMAP dll.

I am trying to install the php_imap.dll extension onto my php server, all I did was set the extensions_dir and then uncomment out the ; in front of the extension=php_imap.dll on my windows XP box which is a php and apache server. When I try and access it I get the error; "Unknown():Unable to load dynamic library 'c:\php\extensions\php_imap.dll' - The specified procedure could not be found." Any ideas?? Thanks heaps, Brent.