http://www.powerquest.com/ support/pr imus/id453 6.cfm
Solution: Error 1523 Cluster beyond end
In this instance, the problem can be resolved by running CHKDSK /R on the affected drive.
For instructions on running CHKDSK, see PowerQuest Solution 2553.
If the error persists after you have applied the recommended fix, please send the following information to PowerQuest Technical Support:
A Debug report (see PowerQuest Solution 101, "Running a Debug Report").
A PARTINFO report created by you. (For information on using PARTINFO, see PowerQuest Solution 62, "Running a PartitionInfo.")
The information outlined in PowerQuest Solution 102, "Information Needed for a Trouble Report."
(If you are running PartitionMagic 6 under Windows Me) The VFNSTDBG.TXT file located in C:\Program Files\PowerQuest\Partition
A copy of the contents of the Master Boot Record captured with WRPROG.EXE. (For information on using WRPROG, see PowerQuest Solution 777, "Instructions for Using the WRPROG.EXE Utility.")
An SSO image of the affected drive (see PowerQuest Solution 227, "Running FSIMAGE").