I am using a OS X.5.5 Server as the backup location and the share point is setup as a Time Machine Backup destination aka the check box, and the permissions are setup correctly.
I had all of the users running on the system except one that was previously working(The physical computer was swapped out, so the hardware address changed). I kept getting a error that the user was not authorized to use the volume. I deleted the users sparse image to zero success. Started and started the client, setup the sharepoint again. Everything I could think of . . . .
I knew that was garbage so I decided to ssh into the volume on the server and look at the share point with the ls -al command.
Low and behold there are files that are hidden security key files and only visable by using the -al modifier.
The control files are all named .HardwareAddress
The backup destination are all networkname_Hardware addresss.sparseimage
The file names correspond to the individual sparseimage file names(networkname_Hardware addresss.sparseimage). You could also locate the offending file name by the owner of the file if your sharepoint is setup that way.
To make a previous time machine backup work with a new Hardware Address or new File Sharing Name, you'll need to rename the networkname_Hardware addresss.sparseimage file to include the new Hardware address or File Sharing name respectivly.
You'll also need to delete the users .HWaddress file if the client doesn't want to connect
