Yeah, I think AB was the first to report how mistakes in scripts can seriously destabilize Opus. While your specific example didn't cause the degree of breakage for me as you saw (folder tree, prefs, etc) it DOES cause the inability to delete files. I've also had it happen where drag and drop operations become unreliable, and drop menu actions using dopusrt do absolutely nothing.
I really hope GPSoft have some control over fencing Opus from these instabilities... but I'm not sure what they'll be able to do. I have taken to the habit of keeping a batch file handy:
del "C:\Users\<my_user_name>\AppData\Roaming\GPSoftware\Directory Opus\Script AddIns\*" /S /QIn order to clear things up - followed by exiting and fully restarting Opus. AB also found that once things are sufficiently unstable, doing a normal exit from within Opus may not actually close the dopus.exe process... requiring you to manually kill it in task manager.
Depending on whether or not GPSoft can do something here - I think it might be helpful for others to be able to start Opus with a safety switch... maybe /noscripts or something like that, just so they can get Opus functional and clean things up easily. I'm content with my batch file, but for others it might be helpful?