Hyperlinks to pdf files not opening

None of the computers on our network, running XP and Office 2003, can open hyperlinks in Excel or Access that point to pdf files. It doesn’t make a difference if the desired files are on the local machine or on the server. All that happens is that Acrobat Reader flashes up and dissapears again. Hyperlinks to other Office documents open with no problem.

I’ve dissabled Windows Firewall, our anti-virus program’s firewall, disabled pop-up blocking in Explorer, but no joy.

Anyone with a suggestion? It would be very much appreciated!