It's one of those words I have to think about before using, every single time. It's misused so often that I expect, give or take a decade, eventually the erroneous application will be acceptable. Language is how the people use it--language comprises incorrect usage that eventually becomes acceptable. Here's the usage note from AHD:

"While this distinction is still maintained by many writers, comprise is increasingly used, especially in the passive, in place of compose: The Union is comprised of 50 states. In an earlier survey, a majority of the Usage Panel found this use of comprise unacceptable."

Things will change as the years pass, and comprise, so used, will be acceptable. The fun is predicting when the blessed event will occur.