Hi Roger, I think you have this problem because your different versions are incompatible. Your versions of clhep and geant4 are too recent for the gate_v3.0.0, and your version of root if it's really the 3.10.02 is too old !  If you have time to do an new installation, I recommend you to take these following versions :           clhep <a href="http://2.0.2.2">2.0.2.2</a>           geant4.8.1.p02           root_v5.14.00d           gate_v3.0.0 or gate_v3.1.1 I personally always take this configuration everywhere I install Gate (I use gate_v3.1.x). Kind regards Simon Stute <div>2007/5/10, Roger Murray Bourne < <a href="mailto:rbourne@med.usyd.edu.au">rbourne@med.usyd.edu.au</a>>:<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Hi All I have downloaded the source code for: clhep v3.10.02 geant4.8.2.p01 root v3.10.02 gate v3.0.0 My OS is Redhat Enterprise 4 for workstations. Compilation of clhep, geant4, and gate appeared to be OK. Compilation of root gave several "non-existent directory" errors. Attempting to run gate from the /benchmarkPET directory gives a segmentation fault. Any ideas? Thanks Roger Bourne University of Sydney _______________________________________________ Gate-users mailing list <a href="mailto:Gate-users@lists.healthgrid.org">Gate-users@lists.healthgrid.org</a> <a href="http://lists.healthgrid.org/mailman/listinfo/gate-users"> http://lists.healthgrid.org/mailman/listinfo/gate-users</a> </blockquote></div>