Custom PHP extensions not woring on windows 2003 server

Hi guys. I have a custom-written PHP extension which is working great on my windows 2000 test server. When I try and run it on the windows 2003 server production server the extension faisl to load. I get a message along the lines of Application popup: Warning : Unknown(): Unable to load dynamic library 'c:\php\extensions\php_SCOGPAAK.dll' - The specified module could not be found. In the event viewer. The standard extensions that come with PHP work fine however. Can anyone shed any light on this? Many thanks. ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. **********************************************************************