External Serial Device or FIR. If i disable this, the serial port is gone,
so i'm pretty sure this is the device.
    

This is really unusual. Do you know what the "external serial device"
actually is?
  
I think it is a serial port when used with a port replicator.
Better send a short output from `irdadump'.
      
I'll send it to you seperatly (but i only states something localhost and
then 1,2,3,4,5,6,* and starts over again.
    
irdadump shows no more then

... 846cdce0 > ffffffff S=6 s=0 (14)
... 846cdce0 > ffffffff S=6 s=1 (14)
... 846cdce0 > ffffffff S=6 s=2 (14)
... 846cdce0 > ffffffff S=6 s=3 (14)
... 846cdce0 > ffffffff S=6 s=4 (14)
... 846cdce0 > ffffffff S=6 s=5 (14)
... 846cdce0 > ffffffff S=6 s=* localhost hint=0400 [ Computer] (25)

and keeps repeating.