Hello,
I use DirectoryOpus 4.12CU addition, and it requires "DirectoryOpus.CFG" to reside in your S: directory. I'm guessing yours will too.
What happened to me was that I could configure DirOpus, but it never saved my settings, yet it said that it had (no error message upon save). Yet when I would quit the program and reload it....my settings would be gone (back to default).
Snoopdos was no help here, nothing ever showed up on snoopdos, infact when it reads the config file it doesn't show up on snoopdos....I just took a guess that the config file should belong in S: and I was right.
So I suggest moving the config file to your S: directory, and see if that fixes it. Good luck.