Thank you for the link.
Unfortunately this did not solve the problem.
Apart from the method described in that post (which did not work) I made many combinations of:
Assign WAV to WMP by means of right click -> choose app ...
Assign WAV to WMP by means of WMP options
Connect/disconnect internal dopus WAV player
Connectt/disconnect Dopus Active X for previewing
Assign WAV to winamp by means of winamp config
Assign WAV to winamp by means of right click -> choose app ...
Directly mess with file associations
etc.
At the end, internal dopus player opens, shows file info but still commands are greyed out
and move the wav file up and down to find the limit.
Althought it is clear, for any casual reader just let me point out that in everyday work it is esy to find longer paths, so please do not show me the non-sense of the the path I wrote above.
The down side for me is that there's no solution as long as I decided to stick with version Dopus v8, and any patch would come for v9
Anyway, if you can reproduce the problem I'll report it to deveopment, just another contribution on my side for the common good.
It's not the length of the path but the depth of the path, I think.
Many parts of the Windows API have a max depth limitation. It's likely not Opus itself but an API which it relies on to play the sound which is going wrong.
It's still worth reporting in case there is something that can be changed in Opus to work around the issue, or in case the problem actually is in Opus.
(Since other aspects of Opus work okay in a deep path I'm guessing the problem is not in Opus itself but I might be wrong.)
Well, having in mind the simple point of view of a plain user, if you can do something with Windows Explorer (can play that wav in sndrec32.exe) that cannot with Dopus (internal player) ... Who would you blame?
I guess you get the point
Just for closing, I also fixed the problem with the mp3 in the same way as with the wav (also on a limited depth path).