I don't know how ShellToys works (you'd have to ask the authors of ShellToys) so I'm not sure if what it does should apply to Opus or not. Opus builds its own context menus so if ShellToys somehow hooks the shell context menu code then it would not affect Opus. But if ShellToys works as a shell extension it should work with Opus.
Make sure you have the 64-bit ShellToys if you are on a 64-bit OS.
The ShellToys authors seem to be aware of Opus (see this thread), but I don't know if that fix was for the context menu part of their tool or some other part. (I'm not very familiar with the tool at all, as you can probably tell.)
FWIW, you can modify the context menus within Opus by itself: Tip: Organise and Speed-Up Context Menus