The message is simply "This application has requested the Runtime to terminate in an unusual way. Please contact the application's support team for more information."
Dopus returns this message when I am logged on as a Power User. It does not return the error when I am logged in as an Administrator.
XP SP3, Dopus v10. I purchased it yesterday, and installed it over v9.
I can only guess but my guess is that the error is coming from a shell extension which is relying on a component or piece of configuration data which is there (or which is writeable) for the admin user but not there (or not writeable) for the power user.
Try using ShellExView, running as the affected account, to disable all shell extensions except for the Microsoft and Opus ones, then logout of the account and log back in with the same account.
Merely toggling everything off, then on, seems to have cleared the problem.
More specifically, I downloaded SellExView (great program btw), sorted the list to show all the non-Microsoft objects together, and disabled all except Opus. I then turned each one back on, one at a time, testing Opus each time. Opus was still running when I turned the last one on, and it is running still.