Although I have not experienced crashing issues with the lighting effects from BCC in AE 7 on MacIntel machines, you might be experiencing a conflict with OpenGL control. AE 7 has OpenGl enabled by default in the comp window - I wonder if disabling this function in AE will do anything to prevent the crashes. If you would like to try that it could help in narrowing down the problem. To disable OGL in AE 7, click on the Fast Previews icon in the comp window and set it to off. Please let me know if this does anything to relieve the crashes.
Meanwhile we would like to hear from any others that are also having this experience.