To rpurdie:
I installed the latest kernel for oz3.5.3, the one for 20050424 iirc. Later, I also installed the kernel-module-serial_cs... from the same directory.
Then, when inserting my socket bluetooth 2.5 rev.G card, I get the following error:
May  5 21:52:06 c7x0 daemon.info cardmgr[2959]: socket 0: Serial or Modem 
May  5 21:52:06 c7x0 user.warn kernel: serial_cs: Unknown symbol serial8250_unregister_port 
May  5 21:52:06 c7x0 user.warn kernel: serial_cs: Unknown symbol serial8250_resume_port 
May  5 21:52:06 c7x0 user.warn kernel: serial_cs: Unknown symbol serial8250_register_port 
May  5 21:52:06 c7x0 user.warn kernel: serial_cs: Unknown symbol serial8250_suspend_port 
May  5 21:52:06 c7x0 daemon.info cardmgr[2959]: executing: 'modprobe serial_cs 2>&1' 
May  5 21:52:06 c7x0 daemon.info cardmgr[2959]: + Using /lib/modules/2.6.11/kernel/drivers/serial/serial_cs.ko 
May  5 21:52:06 c7x0 daemon.info cardmgr[2959]: + insmod: cannot insert `/lib/modules/2.6.11/kernel/drivers/serial/serial_cs.ko': Unknown symbol in module (-1): No such file or directory 
May  5 21:52:06 c7x0 daemon.info cardmgr[2959]: + modprobe: failed to load module serial_cs 
May  5 21:52:06 c7x0 daemon.notice cardmgr[2959]: modprobe exited with status 1 
May  5 21:52:06 c7x0 daemon.notice cardmgr[2959]: module /lib/modules/2.6.11/pcmcia/serial_cs.o not available 
May  5 21:52:06 c7x0 daemon.err cardmgr[2959]: bind 'serial_cs' to socket 0 failed: Invalid argument          
Can you please provide any hint about what to do now?
TIA