Hey Robert,
I use my SPC 900NC (mine has the LONG Exposure Modification with a normal/Long switch allowing me to use it for long exposures), however I dont use it for LE as it is too noisy....
I have found, just like you that when using my philips with PHD, sometimes it fails to activate the camera. I also have K3CCD tools on my PC and IT cant find the picture when PHD is having a tanty as well.
What I do to "wake up" the camera is to close PHD, and then go to the START>PROGRAMS>ACCESSORIES>SCANNER AND CAMERA WIZARD (I have XP.....
That wakes up the camera and then I take a photo with it using the wizard, close it, go back to PHD. Click on the camera button on the bottom left, select windows webcam (NOT LE modded) and then se the colour model to YUY2 640x480.
THEN, what you need to do is set the timer which is probably set to 1.0s to something like 0.1s and then click on the cam dialog button on the right.....set the camera to FULL AUTO and then close that screen, go back to PHD main screen and press the circular green arrow that says, "start looping exposures....." and viola...you should see the webcam on the PHD screen.
It will be bright as the camera is in auto exposure mode, but you should be able to make out stars (it WILL show in B&W) and then all you need to do is start the connection to the telescope via the ASCOM EQ5/6 driver, (assuming you already have the EQASCOM program installed and the PC connected to the handcontroller, via the serial cable to RJ11 into the bottom of the hand controller, with the controller in the utility/PC direct mode)
Once the ascom is connected and running, make sure you click on the sidereal rate button at the bottom of that red and yellow screen (symbol of a star) and then the mount will be talking to PHD and ready to guide.....
If you can see a star, click on it, this will put a green box around it.....keep watching it and if the star fades out every now and then, simply change the timer to say 0.5s or 1.0s, this will mean PHD is stacking webcam frames and creating a better Signal to noise ratio for you just like a Long Exposure Webcam....one reason why you DONT need to run it in LE mode.
Once you click guide (or whatever the button is to the right of the round green arrow - I am doing this from memory), PHD will do a calibration of the mount in W then E, and N then S, and if all is good, will CROSS HAIR your star box (takes about 2 mins) and then PHD is GUIDING!!!! woohoo....
From memory....I might have adjusted my EQASCOM settings to slightly (say 0.4) higher aggressiveness in RA and DEC....something you do by pressing the button with the 3 arrows on it >>> at the top of EQASCOM. This will show the expanded page with other bits and pieces.....
WHEW...this was originally supposed to be a quick instruction on how to get the webcam going....sorry, I seem to have done a brain dump on you.....
If this is confusing, let me know, I can rewrite or help further when I am at home, (at work now

) or even PM me with your phone number and I can call you to help you out...
Hope this helps...
Cheers
Chris