Which version of Microsoft Office do you have installed?
The crashes are due to something corrupting the memory heap, which means the bad code may get away with it and then cause something later to crash, so the dumps aren't conclusive, but... They all point to a shell extension being involved in the crash, and one of them suggests it may be msoshext.dll (part of Office)
I found several threads, and hotfixes for various versions of Office from 2007 right up to 2013, about msoshext.dll causing lots of crashes in Windows Explorer, and those would affect Opus as well, so disabling that shell extension (and/or checking for any updates or optional hotfixes for your version of Office) is a good place to start, to see if it helps.
You can disable it using ShellExView. (Make sure you get the 64-bit version of it.) Scroll it over to the Filename column and sort by that, then Ctrl-F and paste msoshext.dll to find the extensions which are related to that DLL.
With my version of Office I get three different extensions, with the following full path, but it may vary with other versions:
C:\Program Files\Common Files\Microsoft Shared\OFFICE14\msoshext.dll
Select them all and then right-click and choose Disable Selected Items.
Then exit Opus (don't just close the windows; fully exit Opus; or reboot if you want to be extra sure) and see if the problem still happens.
If you do still see a problem, you'll probably need to start disabling other shell extensions to work out which one is going wrong.