I've got the same problem. It's only with wma files. It's pretty inconsistent.
Sometimes, not always, when I play a wma song, I'll get error message:
"Error: Playback Engine: Media Jukebox is unable to acquire license for this file. Windows Media Error: 0x80070020"
If the song is able to begin playing without that error, then the error will happen at the end of the song. This is always. I'll get a message that MJ has encountered a problem and has to close./Send message to MSFT?
In the last two weeks, I've installed WMP 9, XP SP1, and MJ 8.0.370. And today was the first time I tried to play a wma file during this time, so I can't point at one of them.
Also, a few days ago, I lost sound in one speaker. I think it's a hardware problem, but if anyone can suggest a possible software cause, please let me know.
Media Jukebox PLUS 8.0.356
Install Path: C:\Program Files\J River\Media Jukebox\
CPU: Intel Pentium 4 1793 MHz MMX
Memory: Total - 523 MB, Free - 287 MB
OS: Microsoft Windows XP Workstation 5.1 Service Pack 1 (Build 2600)
Internet Explorer: 6.0.2800.1106
ComCtl32.dll: 6.00.2800.1106
Shlwapi.dll: 6.00.2800.1106
Shell32.dll: 6.00.2800.1106
wnaspi32.dll: Internal ASPI Layer