I'm having the same problem, interesting thing, I noticed when I unplugged the TM751 altogether, I was able to swithc cameras no problem in Vanguard using my mouse on screen, but when a motion detector tells it to switch cameras, it switchs from one grid cell (of the 4 grid view) to the next, but the video from the previous cell shows up in the new cell (it didn't switch feed). THis is odd because I was able to switch LIVE FEED (i tested it was live) by just clicking with the mouse. Apparently you don't need the TM751, it's communicating some other way(or maybe not at all just switching the frequency that the receiver is listening to) but doesn't switch when motion activated. Very odd. I expected no camera switching WITHOUT the TM751, and here it worked even better in Vanguard, except when a motion detector tells it to switch. This would go against X10 claim that the cameras are broadcasting on the same freq and that the receiver can't tell which camera is broadcasting, but apparently not, because obviously without the TM751 I can't tell the system which camera to activate, unless my security system is doing the X10 broadcasting over the housewires and the TM751 was creating an echo or something. If that's the case and I am in fact broadcasting an X10 signal over the houseline via my Security system being plugged in, why can I switch cameras manually no problem with my mouse, but the motion detector can't. Again, the motion detector in fact sends a signal to the firecracker and activates the software, but the software changes the grid cell of the 4 view grid but uses the previous camera view.