I can't explain the success - but I'll take it anyway. :-)
When I build the CamelBones Xcode project with Xcode 2.5 on Tiger/Intel, the resulting 5.8.1 support module runs fine on Panther. The same project, built with Xcode 3.0 on Leopard/PPC, fails on Panther. Same .xcodeproject bundle, unchanged settings, same code, etc. - I can't imagine a reason why Xcode 3.0 should be producing different results, so at this point I'm beginning to suspect a compiler bug. Not only do ShuX and Atlantis both run on Panther, ShuX does so without the bugs that are immediately apparent when the Leopard build runs on PPC/Leopard. I suspect that maybe the PPC tool set isn't getting much love from Apple lately. :-(
So the solution, it seems, is to build the Panther support bundle separately, with Xcode 2.5 on Tiger. Kind of a pain, and it's probably an issue worth revisiting with future Xcode releases, but I can live with it for the sake of shipping sooner rather than later.
Cocoa programming in Perl: http://camelbones.sourceforge.net