Hello Marc,
Yes, you should receive a 70% discount when upgrading from DR 4.1 to DR 4.2 according to our Upgrade Policy:
http://www.datasprings.com/support/...ade-policy Also, before upgrading, I would recommend performing a back up of your current site, install the DR Trial version from the link I provided, install it, and see if this issue still persists.
If it does, then you'll have the option to rollback to the version of your site with DR 4.1 installed. I bring this up because you can't downgrade our modules without conducting an uninstall/reinstall(which will remove all of your work done in DR).
I've seen Dynamic Registration conflict with other modules, generally jQuery conflicts. So you may want to download FireBug plugin for FireFox, throw DR and the messaging center on the same page, enable FireBug and see if any Conflicts/JavaScript errors were logged.
Please let me know if you have any questions.
Thanks,
Ryan