Ok, first off.. I have posted this over on the Photopost support area, and so far have not managed to get a resolution.
I appreciate this is a "server side" error, but the facts are that prior to upgrading Photopost 4.7j to 5.1 this process worked fine, so it HAS to be something that has changed in the code that is causing this.
Basically, when you upload an image, after you click the upload button, 20 seconds later you get the error. If you select the bulk option to use files from the upload directory on the server it happens straight away.
Everything else seems to work in 5.1, and everything else on the server PHP based, UBB etc, works perfectly.
I've upgrade to the latest version of PHP. The server is 2003, IIS6, SP1, so the MS fix for the known CGI issue is already applied.
If anyone can help.. that would be great, otherwise its going to have to be removed..