Connecting to serial port

[Steve Douville]

I'm trying to connect to the serial port of a Dell PowerConnect 3024.  I've connected a null modem cable between them. During boot, this is what is happening:

Feb 11 00:34:17 server2 kernel: sio0: configured irq 4 not in bitmap of probed irqs 0
Feb 11 00:34:17 server2 kernel: sio0: port may not be enabled
Feb 11 00:34:17 server2 kernel: sio0: <16550A-compatible COM port> port 0x3f8-0x3ff irq 4 flags 0x10 on acpi0
Feb 11 00:34:17 server2 kernel: sio0: type 8250 or not responding

Can anyone shed some light on what I might have done wrong or where to continue looking? 

Thanks!