Microsoft Outlook cannot launch an application to handle *\\????\apps\

I have followed the instruction to create Outlook Templates from this site, I created a new toolbar etc as per instructions, but when I try to open the new template I get the following message:

Microsoft Outlook cannot launch an application to handle *\\?????\apps\popp.oft*. The URL may be incorrect, or you may need to install an application to handle this type of URL

the ????? in the above link are in place of our server name. Any ideas?

Thanks