Journaling problem

[Steve Buehler <steve ibapp com>]

	I have a RHEL ES 4.1 system and some commands are giving me 
input/output errors.  For instance, when I try to run a "du" command, I get:
[root]# du
-bash: /usr/bin/du: Input/output error

We rebooted the server and the only error that it came up with was 
the following:
"EXT3-FS error in start-transaction: Journal has aborted"

I googled for the above, but can't find anything like it when I 
search for (without the quotes):
"EXT3-FS error in start-transaction: Journal has aborted"

I can't grep or cat the /var/log/messages log file because I get an 
Input/output error:
[root]# cat messages|grep journal
cat: messages: Input/output error

if I grep the /var/log/boot.log for the word journal, this is all I get:
[root]# cat boot.log|grep journal
Aug 12 09:21:02 servername fsck: /boot: recovering journal

If I do a "dmesg|grep Journal", I get about 50 rows of the following:
[root]# dmesg|grep Journal
EXT3-fs error (device sda2) in start_transaction: Journal has aborted
EXT3-fs error (device sda2) in start_transaction: Journal has aborted

Does this mean my sda2 Raid is failing?  After a normal boot, I can't 
run fdisk because I get:
[root]# fdisk
-bash: /sbin/fdisk: Input/output error

Here is the output of a df command.  The /dev/sda2 is a raid 5 system 
with 4x250GB SATA drives.
[root]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda2             685G   46G  605G   8% /
/dev/sda1            1004M   25M  929M   3% /boot
none                 1014M     0 1014M   0% /dev/shm

I co-locate the server, so I can't sit in front of the console myself 
to see everything.  I can ssh into the root account remotely though.

Any help would be appreciated.
Thanks
Steve