Hi-
This line in your ~/.cshrc file is misspelled:
setenv DYDL_LIBRARY_PATH /opt/X11/lib/flat_namespace
you can open it (for example, on a Mac: open -t ~/.cshrc) and copy+paste this over it:
setenv DYLD_LIBRARY_PATH /opt/X11/lib/flat_namespace
Then, source the file (e.g., via: source ~/.cshrc) or open a new terminal, and try your GUI again.
--pt