Tried SL clean install from Tiger, now can't access external HD

[headofthesound]

After many mis-steps I was able to install Snow Leopard. This was a more involved process than I had first anticipated, I was using Tiger before.

I backed up everything on an external hard drive. SL seems to be running OK and I'd like to get my files back. BUT my Macbook doesn't recognize my external hard drive. I can view it in Disk Utility, but I can't repair or verify it. When I try to repair, I get the message: Disk Utility stopped repairing "X" / 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.

How can I get my apps, music, photos, ect. back on my computer?

 

[headofthesound]

phew, fixed: hooked the external HD to another Mac, it had no problem recognizing said HD, hooked it back up my Macbook and now it recognizes the previously unrecognizable.

Does anyone know why this fixes the problem?