I used your importer, tanks for that! It doesn't work flawlessly but it's a start.
However, it imports QML files only if I'm correct. I could not succeed in exporting questions from Questiomark version 4 to QML-format.
If you wish you can download Questionmark Perception from the website and use it for 30 days. Just go to http://www.questionmark.com and press download. You need to register and get an Email with a password, but it's all free of charge.
I can also send you some QMP 4 repositories that I would love to use in the Moodle Quiz Module. They are in Dutch though.
You can reach me at firstname.lastname@example.org