I've read in this forum and on the website that the watermark logo that appears on the free version of Prince does not print. I've downloaded the Linux free server version, and the PDFs that it generate have watermark logos that do appear on the page when printed. Am I doing something wrong or just misunderstanding something?

How did you print the PDF file? It could be a bug in the PDF viewer, as if you print them from Acrobat the watermark is not printed.

I'm using Evince in (Linux), but I think the same thing happens when I print using KPDF (Linux). I just tried it from a windows machine with Adobe Reader 9 and the P doesn't print. Is this a defect in my reader that is causing this?

Yes, annotations can be printable or non-printable, and I suspect that Evince and KPDF are not handling this properly.

I have evince 2.24.1 (Ubuntu Intrepid). If you print to file you can create a pdf that does not have the prince logo.