OS X V10.7 Lion :: "You Are Unable To Login To The User Account "xxxx" At This Time"

i am currently trying to set-up a wireless network at home using Lion Server, and it would appear I have bitten off more than I can chew. I installed Lion Server on Tuesday, and have been battling with it ever since - attempting to use a 'We Got Served' guide to walk me through.  

I installed the Server app on my iMac as I figured the 3 computers on the network would not require very much space, and so there would be little point in buying a whole new machine to run it from. Whilst I was having little luck in making it work as I had hoped - I have now managed to completely lock the iMac. Since it's installation I have had no issue logging in and out of my actual account on OSX, however earlier the computer froze following an Adobe update and I was forced to do a hard restart. However, when I attempted to log back in I now get the following error: 

"You are unable to log in to the user account "xxxx" at this time. Logging in to the account failed because an error occurred." 

I have tried everything in my limited knowledge to rectify this, and nothing works it would seem. I've read examples of this happening when trying to log into the actual server app, or where the hard drive is corrupt on the machine itself - this seems to be a hybrid of the two. 

I can no longer open the computer in Safe Mode, however when I go into Disk Utility all disks when verified appear to be absolutely fine with disc repair making no difference. The only available drive is now listed as a Server drive so I cannot even re-install Lion on there.  

This is causing me much distress as I can as far as I can tell not only log into my computer, but can do nothing to repair the issue bar erasing everthing from it. There is a lot of important data on there and I am confident that it is not actually corrupt, however Server seems to have just locked it completely.