Off-hand I can't think of anything that changed in 9.1.0.4 that could have affected this.
Were you previously using 9.1.0.3 or have you upgraded from an older version?
Have you recently updated Spybot?
Opus saves minidump debugging files in %TEMP%\DOpus.Minidumps when it crashes - if you want to upload the most recent one we can take a look at where the crash might be occurring.
Yes, i did use 9.1.0.3 before, haven't had a crash then.
I only update the Spybot signatures when they are updated.
Haven't changed the core Spybot program.
I look in that folder, but all minidump files are 0 byte sized.