[Chimera-users] problems before even getting to the plate...

Howdy, Trying to run latest Chimera release version 1.3.2577 on my OSX 10.4.11 with X11 version 1.1.3 and while the chimera program opens, I cannot open a PDB (or at least I can't see the opened PDB - no error message, and bottom left of chimera screen states "Opened XXX.pdb" for about a minute until it goes to blank). Should I try installing an older version of chimera? Any help would be much appreciated. Thanks, Jon