PDF Creator Server not printing

Hi,we've been trialling PDF Creator Server 2.2.0. It was working successfully when first installed i.e. we were able to print to the shared printers from other servers.
We've come to test today further and all documents are "sticking" in the application Spool folder and no PDFs are produced.

The event log tells us:
[Debug] pdfforge.PDFCreatorServer.Service.PrintJobSource.Program.Main: PrintJobSource called with inf file: C:\Windows\TEMP\PDFCreator Server\Spool\9-6EE1C61AB2AC4BCC82D274489C936F8F.inf [Debug] pdfforge.PDFCreatorServer.Service.PrintJobSource.Program.Main: Pipe server PDFCreator-Server not found

Please could anyone advise?