Hoi, I forgot: You don't need to have ROOTSYS set. It seems that srtpath does it for you (now). If you don't want to run the srtpath every time, use the following root version on SL3: setenv ROOTSYS /afs/slac.stanford.edu/g/babar/package/root/4.01-02/Linux24SL3_i386_gcc323/ and don't forget LD_LIBRARY_PATH. Cheers, --U.