Jack,
Here and in the only customer where I've already updated to PDFX5, CTRL+P in an XTREE hangs A-Shell.
Does this happens with you or you need more details?
PS: In the process of verifying this on my computer, I noticed the existance of the PDF virtual printer created in XTREE printing, maybe the crash is related to this but, accidentaly, I've deleted both the virtual and the PDFX printer itself so, I have to reinstall it before further tests (after dinner).