Looks like you're using a uid_t to receive a DBUS_TYPE_INT64 off the bus, which probably accidentally works ok on a little-endian system, but breaks on a big-endian system. So on my powerbook, it thinks the received uid is zero.
Created attachment 989 use dbus_int64_t instead of uid_t
Committed with revision 24957. 2007-02-12 Benedikt Meurer <benny@xfce.org> * terminal/terminal-dbus.c: Apply Brian's patch to fix invalid variable type for user id. Bug #2898.