Odd.
WMV is a supported filetype. Not an optimal choice, but, as it has for you in the past, should work.
It is tempting to look at transcode settings or the settings you used to export it from PR. But the more likely scenario is that something changed on your machine in terms of codecs or other settings.
You mention building to a folder, but I assume the problem has nothing to do with a build. When do you get the error? Upon import of the asset? Or trying to transcode it? I assume it is not when you open the project.
