External Drive is no longer recognized by Macbook

Question

I have this external drive....
http://www.amazon.com/Western-Digital-Passport-Essential-WDME2500TN/dp/B0012GK3M Q/ref=sr11?s=electronics&ie=UTF8&qid=1280159206&sr=1-1
It is about 60% full of music/pictures/documents that are NOT on my Macbook, therefore I use it regularly.
Every once in a while, I accidentally remove it without properly ejecting first. But I guess I did it one too many times because now the computer will not recognize it at all.
To insure that the drive wasn't corrupt, I plugged it into a PC. It worked fine. The files are all there and were completely accessible. But as soon as I plugged it back into the Mac, it won't show up.
When I try a Disk Utilities repair, I get the following message:::::
FIRST AID FAILED
Disk Utility stopped repairing “My Passport” because the following error was encountered:
The underlying task reported failure on exit
Verify and Repair disk “My Passport”
** /dev/disk1s1
** Phase 1 - Read FAT
** Phase 2 - Check Cluster Chains
** Phase 3 - Checking Directories
Unable to read directory (Input/output error)
Error: The underlying task reported failure on exit
1 non HFS volume checked
1 volume could not be repaired because of an error
I have NO $$$, so telling me to purchase a $30-100 program will not help me AT ALL. I'm looking for solutions that will not effect my wallet, even if they take all day to complete.
What can I do????????

Answer 1

Ok. Just to set one part straight- I doubt the problem came from unplugging your drive without ejecting. This usually isn't a problem unless files are writing or in use when you do it, but ejecting is a safe way to avoid issues.
Try force-mounting the drive in terminal by using the following commands
*mkdir /Volumes/yourdrivename*
this command should give you the location of the drive on your computer. (It should be something like disk2 or disk1s3) Then type the location into:
*mount /dev/yourdrivelocation*
Whether or not this works, follow up this step by ejecting the drive and unplugging and plugging it back in. This worked for me when I was having this issue.
Also- are you able to backup and reformat the drive? This would be a good thing to try if other attempts have failed.