You have not provided any useful details about the actual footage, but if the error occurs with multiple clips, then most likely you are using wrong recording settings on your camera or the clips are damaged/ malformatted. On the other hand you could be using some crappy "CoDec pack" on your system that makes a mess of Adobe's own CoDecs or the chosen format not be CS& compatible in the first place. Impossible to tell based on your insufficient information.
As a result of your advice, I pursued the settings angle. I converted the file to a 29.97 frame rate in an MP4 format that I usually use using Handbrake and now After Effects is working normally. Apparently it was a problem with the camera settings. Some Brits were in town, borrowed my camera, and must have changed some of the camera settings. I'll have to figure out how to get it back to my standard settings. But the bottom line is that I'm back in business. Many thanks!