Universal preference pane is forced to launch on 32-bit

I'm building a Preference Pane for an application, it's Universal (PPC/32-bit/64-bit) but when I install it on the System Preferences, i'm forced to run it on 32-bit. Any idea why and how to solve it?

if i run file FILE_PATH i get:

FILE_PATH: Mach-O universal binary with 3 architectures
FILE_PATH (for architecture x86_64):    Mach-O 64-bit bundle x86_64
FILE_PATH (for architecture i386):  Mach-O bundle i386
FILE_PATH (for开发者_运维技巧 architecture ppc7400):   Mach-O bundle ppc

so,i can confir is universal, but evrn that verified, i'm forced to run it on 32, please help.

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64 bit preference panes need to use garbage collection, see this Apple document. Have you turned it on?