As a Beta, WMP11 is bound to have issues now and then which may only be fixable through a patch/update from Microsoft. However, here are two things I'd try:
1.) Go Start->Run and type in regsvr32 wmp.dll (with the space). A moment later you should receive the notice "DllRegisterServer in wmp.dll succeeded." Restart your computer and see if the issue is resolved.
2.) Try reinstalling WMP11 using the original installer from Microsoft...it should replace and re-register all associated files and registry entries.
Hope this helps,
Appname:wmplayer.exe AppVer:11.0.5358.4827 ModName:
ModVer: 11.0.5358.4827 Offset:0003a72b
debug or close if i click close the player close. any idea.