Can't mount formatted external disk

I decided to format my Lacie 160 Gb firewire external drive yesterday. I used disk utility and chose to erase with the zero out data option.
Today, I unplugged the drive and plugged it back in later. I want to mount the disk, but nothing happens. Not sure what I need to do????

 

I just left it when I went to bed last night.
When I woke up my Mac this morning the disk icon wasn't there.
That's when I unplugged and replugged it. A message came up that disk was unreadable (with options to stop, eject or initialize)
I chose initialize and got the disk utility screen.
The Group SA is shown as:
Disk Description : LaCie Group SA Total Capacity : 160.04 GB (160,041,885,696 Bytes)
Connection Bus : FireWire Write Status : Read/Write
Connection Type : External S.M.A.R.T. Status : Not Supported
Connection ID : 58629636519016050 Partition Map Scheme : Apple Partition Map

but the disk itself has the shaded grey font.
I tried verifying and repairing and got this:
Verifying volume “disk4s6”
Error: This disk needs to be repaired. Click Repair Disk.
Verify and Repair volume “disk4s6”
Volume repair complete.Updating boot support partitions for the volume as required.Error: Disk Utility can’t repair this disk. Back up as many of your files as possible, reformat the disk, and restore your backed-up files.

The drive dates back to 2006.

 

Thanks for the tips. I'll try them later and let you know!

 

It worked. Thanks a bunch!