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.

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