Help Needed! I-book does not recognize Lacie 160GB external hard drive

My lacie 160 GB external hard drive does not mount. Something went
haywire when i was trying to change the access privleges. I was trying
to set it so only one user can access the hard drive. Somehow i ended
up locking myself out. When i logged out and logged back in the hard
drive was not mounted at all. I have tried everything to get it to
appear on my desktop again. I know it's not a coord problem because the
disk is recognized in disk utility and system profiler. However, the
button for "repair disk permissions" in the disk utility is not
available. I have a ton of files on there, so i need to somehow get
back in. Any ideas?