Thanks for The Keep - I'm finding it quite helpful and feature-rich.
I had only FoxIt installed for viewing PDFs, and once I added a PDF to my campaign in The Keep, I downloaded the latest version of Acrobat Reader (9.1) from the Adobe site. Afterwards, every time I selected the PDF within The Keep, the application crashed.
After uninstalling Acrobat Reader 9.1 and installing 8.1.4, The Keep works fine.
Just thought you should know that there is apparently an incompatibility with the current version of Reader.
I am running Windows Vista.