ejabberd's extauth run well in Debian 5.0 32bit, but it cannot run under Debian5.0 x86_64bit

I installed ejabberd 2.1.1 with external authentication by python script under Debian 5.0 32bit. It is running well.

now, i want to move ejabberd to Debian 5.0 64bit, the problem happened:
The same config and same scipt as 32bit os, but ejabberd cannot running with external authentication, the main process "beam.smp" is here, but the external authentication process cannot be found.

And ejabberd.log recorded as :

=INFO REPORT==== 2010-01-18 23:42:08 ===
I(<0.37.0>:ejabberd_app:84) : ejabberd 2.1.1 is stopped in the node ejabberd@localhost

=ERROR REPORT==== 2010-01-18 23:42:11 ===
C(<0.277.0>:extauth:91) : normal

Does anyone can help this? So Strange!!!