Hi All, I have installed Gate and This is my congiguration of env_gate.csh , the problem is at the bottom. On this machine the G4SYSTEM=Linux-g++ On this machine the G4INSTALL=/usr/local/gate/gate_v3.1.2/geant4.9.0.p01 On this machine the G4INCLUDE=/usr/local/gate/gate_v3.1.2/geant4.9.0.p01/includeOn this machine the G4LIB=/usr/local/gate/gate_v3.1.2/geant4.9.0.p01/lib On this machine the G4LEVELGAMMADATA=/usr/local/gate/gate_v3.1.2/geant4.9.0.p01/PhotonEvaporation2.0 On this machine the G4RADIOACTIVEDATA=/usr/local/gate/gate_v3.1.2/geant4.9.0.p01/RadioactiveDecay3.2 On this machine the G4LEDATA=/usr/local/gate/gate_v3.1.2/geant4.9.0.p01/G4EMLOW4.3 On this machine the G4NEUTRONHPDATA=/usr/local/gate/gate_v3.1.2/geant4.9.0.p01/G4NDL3.11 On this machine the CLHEP_BASE_DIR=/usr/local/gate/gate_v3.1.2/CLHEP-<a href="http://2.0.3.1" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">2.0.3.1</a> On this machine the CLHEP_INCLUDE_DIR=/usr/local/gate/gate_v3.1.2/CLHEP-<a href="http://2.0.3.1/include" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">2.0.3.1/include</a> On this machine the CLHEP_LIB_DIR=/usr/local/gate/gate_v3.1.2/CLHEP-<a href="http://2.0.3.1/lib" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">2.0.3.1/lib</a> On this machine the CLHEP_LIB=CLHEP On this machine the G4VIS_BUILD_OPENGLX_DRIVER=1 On this machine the G4VIS_USE_OPENGLX=1 On this machine the OGLHOME=/usr/local/gate/gate_v3.1.2/geant4.9.0.p01/Mesa-7.0.1 On this machine the XMFLAGS= On this machine the XMLIBS= On this machine the XMFLAGS= On this machine the XMLIBS= On this machine the XAWFLAGS= On this machine the XAWLIBS= On this machine the G4LIB_BUILD_SHARED=1 On this machine the G4LIB_BUILD_STATIC=1 On this machine the G4UI_USE_TCSH=1 In your environment you have the G4WORKDIR=. LD_LIBRARY_PATH is set to include CLHEP and Geant4 libraries. NOTE : verify that the correct path for the CLHEP library - $CLHEP_BASE_DIR/lib - is included in the $LD_LIBRARY_PATH variable in your environment, and no other outdated installations of CLHEP are by chance referenced through $LD_LIBRARY_PATH and present in your system ! Configuring GATE options G4WORKDIR set to . G4TMP set to ./tmp G4BIN set to ./bin Data analysis and output features enabled Ascii data output enabled Transport and generation of optical photons is enabled Checking your LD_LIBRARY_PATH variable... ==> OK: /root/scratch/gate/gate_v3.1.2/root_v5.14.00h/lib added to your LD_LIBRARY_PATH Use of ROOT enabled ROOT real-time plotter disabled Checking your LD_LIBRARY_PATH variable... ==> OK: /usr/local/gate/gate_v3.1.2/lmf_v3.0/lib added to your LD_LIBRARY_PATH LMF data output enabled ECAT7 data output enabled GATEHOME is set to /usr/local/gate/gate_v3.1.2/gate_v3.1.2 Checking your path variable... ==> OK: /usr/local/gate/gate_v3.1.2/gate_v3.1.2/bin/Linux-g++ is already in your path variable G4VERSION8 is not set: GATE is not compatible with the geant4 version 8.1.p02 G4VERSION9 is set: GATE is compatible with the geant4 version 9.0 And when i am doing PreInit> /control/execute benchmarkPET.mac /control/verbose 0 parameter value not listed in candidate list. *********Illegal parameter (0) </vis/open OGLSX>****** please can anyone let me whats wrong with my configuration. Thank You, Ruchir Bhatt