Disk Warrior Cannot Rebuild Disk

I'm using Mail 2.0.5 with OS X 10.4.3 (Tiger). Until recently, I've had no problems with the Mail program, but for the past 36-hours or so I've not been able to Send mail from this computer. Receipt is no problem. I get the typical message which says "Cannot send message using the server ____." No other servers work either, but they only don't work on this computer*. They...

Have a drobo disk unit with 2.7Tb of storage on it. ...

minutes, it got no further and I could not hear any disk activity. ...

Disk Warrior can't even rebuild the directory, as it claims the drive is too corrupt. ...

a fairly unaninmous REFORMAT! I did that and I did not have any troubles. Lately though I have ran into the same thing. Now there are some files on my HD that I cannot get off because it says data in a certain file cannot be read or written. ...

of contents is scattered, but cannot rebuild as it won't boot off a CD. ...

No, I get this more often than I like. Disk First Aid is a pretty wimpy utility and cannot rebuild file systems like some paid software can. ...

The System Software on the startup disk only functions on the original media, not if copied to another drive. ...