I lost IFEFFIT after upgrading to MAC OS X 10.4 (Tiger). Apparently, this is due to the fact that the upgrade replaced Perl 5.8.1 by Perl 5.8.6. I redid the IFEFFIT installation (for 10.3), which created a Perl5.8.1 folder with all the goodies. However, as the following error message shows, the system is not happy and is looking for some stuff in the new PERL. And does not find it. I'm not sure how to revert to 5.8.1, or alternatively more everything to the new 5.8.6. Hopefully this is a trivial question :-) Thanks for any help, JOEL [JoelG5:/Applications/Ifeffit/bin] joelb% ./hephaestus Can't load '/Library/Perl/5.8.1/darwin-thread-multi-2level/auto/Tk/Event/Event.bundle' for module Tk::Event: dlopen(/Library/Perl/5.8.1/darwin-thread-multi-2level/auto/Tk/Event/Event.bu ndle, 1): Library not loaded: /System/Library/Perl/5.8.1/darwin-thread-multi-2level/CORE/libperl.dylib Referenced from: /Library/Perl/5.8.1/darwin-thread-multi-2level/auto/Tk/Event/Event.bundle Reason: image not found at /System/Library/Perl/5.8.6/darwin-thread-multi-2level/XSLoader.pm line 68. at /Library/Perl/5.8.1/darwin-thread-multi-2level/Tk/Event.pm line 10Compilation failed in require at /Library/Perl/5.8.1/darwin-thread-multi-2level/Tk.pm line 13.BEGIN failed--compilation aborted at /Library/Perl/5.8.1/darwin-thread-multi-2level/Tk.pm line 13.Compilation failed in require at ./hephaestus line 54.BEGIN failed--compilation aborted at ./hephaestus line 54.Undefined subroutine &Tk::Event::CleanupGlue called at /Library/Perl/5.8.1/darwin-thread-multi-2level/Tk/Event.pm line 3.END failed--call queue aborted at ./hephaestus line 54.