Video not showing in WMP ActiveX control

Question

Trying to play an MP4 in Windows Media Player and I get a black control and WMP acts as if it is playing.  The MP4 does not have audio but other posts have suggested this is not affected by this issue.  I have tried all of the various solutions from other posts (converting to WMV, tuning off acceleration, ensuring WMP and refnums are closed properly) and nothing seems to work.
I've been able to get the video to work at times, but after it starts to flake out (black) it never seems to recover.  If I recreate the container it always works for at least one play.  It does not matter if I allow it to play all the way to the end or click on the control (and stop it via the event case) -- the error can occur either way.  
At times I have recieved an error (-2147417846) but this does not seem to be required in order to get the no-video effect (effect happens w/ or w/o the error).  I have not been able to track down details on the error but the 750ms delay seems to help with respect to occurence rate. 
When I get the black control, the background shows various other video effects both inside and outside of the ActiveX container.  See the "while_running.png" attachment.  After I stop the VI, the screen looks as in "after_stopping.png".  The "after stopping" look persists until I move the screen (and thereby force a redraw) even a little.
I do not recall installing any special CODECs, etc. and the videos all work fine repeatedely in stand-alone WMP.
Running:
  Win 7 (32) Home Premium SP1
  LV 2011 Pro
  WMP 12.0.7601.17514
Attachments:
playMovie.vi ‏22 KB
while_running.png ‏50 KB
after_stoppin.png ‏146 KB

Answer 1

@Norbert - your callback approach allowed the video to play repeatedly on both test machines, however...  Once you had me apparently past that hurdle I tried to figure out a way to keep the activeX control from resizing (autozoom to video files native size).  I searched through all prop and methods and tried everything I could think of but could not figure it out.  Fine, failing that, I tried to set the window size based on the resulting autosized activeX container with the WMP controls cropped ooutside the front panel window.  That broke the second playing of the video again. 
@Dan - thanks for continuing to look at this.  From my perspective, it feels like the bit that gets corrupted (or set-but-then-not-unset-on-exit-of-first-video) has to do with zoom/scaling or aspect ratio, if that helps.
Trying to make progress, and not finding any exposed WMP props for setting the player size in the ActiveX container, I tried loading the WMP inside a web page inside an ActiveX container per http://zone.ni.com/devzone/cda/epd/p/id/4540.  This gets me around the uncontrollable autosizing of the original VI (now cotrolled by the HTML layer) and also the no-video issue but introduces a new one -- clicking "stop" on the second-played video often results in a bad refnum passed to the "click" invoke inside the "stop" event case.  The VI stops but the video/audio keep going.   I thought it might be a reload-from-cache effect so I modified the "modifyHTML" subVI to save to a unique temp html file evey time and pass that path (as string) to the URL property in WMPBrowser -- no effect.