Audacity changed to the new FFMpeg 2.2.2 library. The entry in the audacity.cfg is always reset to "...\\avformat-52.dll" whereas with release of Audacity 2.0.6 the new avformat-55.dll is used. the older one is not recognized anymore.
The entry in launcher.ini (line 56) has to be changed from
This can also be used as workaround until an updated build is released.