Without seeing the actual scene layout nobody can tell you much nor have you provided any proper system info. Could just as well be that you are on an unsupported configuration and the shaders fail. also check whether your light has a falloff as opposed to being infinite.
Ok. I didn't realize I could include images here. I'll do that. My config is an iMac 27, Yosemite, 2.7 ghz i5.
Here is the comp with the movie background, the text and the light. The text is actually red but shows black.
The light is right next to it.
Here is the TOP view. Things seem to be all over the place. The text is in the upper right and
the camera is at the bottom. The light doesn't show at all. I must be doing something very wrong.
I added another light and can't make that work, either.
Tiny screenshots that don't show layer properties are useless. Show us your entire AE window and select the layers that are giving you problems and press the U key twice to reveal modified properties. Show us 4 comp views. Then take the screenshot and just drag it into the Reply field on this forum. I don't see a light anywhere in your comp. You didn't outline your workflow. Have you gone through any of the training materials found when you type Camera Tracking in the Search Help field at the top right corner of AE?
Gee. Are you always this condescending? I'm the one admitting to NOT being an expert. Sorry I didn't meet your help request requirements. Perhaps you could try to be a little less holier-than-thou with your responses. Would be nice.
My workflow was to create a new comp. Add a movie. Track the points. Select the location. Right click to add a text layer. Position the text. Add a light to the scene to light the text and get a shadow. Text turns black with no light and no shadow.
In that screenshot, it looks like the light isn't pointing towards your text. To test if this is the case, change your light to a point light instead of a spotlight and make sure the falloff is set to infinite. If your text turns red, you've found the issue.