The crash is happening in a thread created by MSVCR90.dll, which is not part of or used by Opus. Unfortunately, the crash dumps did not reveal much more than that.
I would follow the steps in our Crash, exit or high CPU when viewing certain directories guide for disabling shell extensions, since the MSVCR90.dll is almost certainly being brought into Opus by one of them.
(It could also be a viewer plugin, if you have any third party ones, but none of the ones that ship with Opus use MSVCR90.dll so you can ignore viewer plugins unless you've installed some extra ones from the forum.)