SLES 10 SP2 multipath

[lorenzomaurizi]

Hi all,
I need some help about configuring the multipath in an IBM Blade server with Qlogic Fibre Channel HBA.
I followed the instruction given in the Knowledge Base documentation to activate the multipath daemon (How to setup / use multipathing on SLES) but without creating a multipath.conf file.
Now I have a multipath device in /dev/disk/by-name, and the multipath -ll command gives this result:

3600a0b800035ebab000006044874744e dm-0 IBM,1726-4xx  FAStT
[size=40G][features=0][hwhandler=0]
\_ round-robin 0 [prio=1][active]
 \_ 3:0:1:0 sdc 8:32  [active][ready]
\_ round-robin 0 [prio=0][enabled]
 \_ 3:0:0:0 sdb 8:16  [failed][faulty]

Looking in the boot.msg file, I see that /dev/sdb starts to give
<4>end_request: I/O error, dev sdb, sector 0
<3>Buffer I/O error on device sdb, logical block 0

and it goes on continuously.
What should I look to? Sorry for a dumb question but I am totally novice on administering SUSE in a blade environment (and I am not an expert in Linux in general, too).

Thanks in advance for any help.