Thanks Rick! Modifying the .cshrc worked. Just so others don't run into this problem, I might recommend changing the AFNI installation notes for Mac OS to suggest that both the .cshrc and the .bashrc need to have DYLD_LIBRARY_PATH adjusted (right now, step 1b says that either bash or tcsh syntax can be used, which is where I ran into a problem).
Thanks again for your help!
Jeff