It sounds like there could be bad sectors on the disk.
if you ran a fixmbr on the disk. That wipes out the instrumentation data for BootGuard on the disk as well as the pointers to the primary and backup user records on the disk. This makes recovery a little bit more difficult. In the future, I would always recommend copying the data off the machine first before attempting any type of decryption/modification of the disk drive. If you suspect possibly a bad drive, run checkdisk and things like that (after copying what you can off the drive).
One thing you could have them attempt is to slave that hard drive that is having trouble back into a PC with PGP Desktop or Symantec Encryption Desktop. Then open up a command prompt and cd into the Program Files (x86) (64-bit) or Program Files directory for PGP.
example on 32-bit:
cd c:\Program Files\PGP Corporation\PGP Desktop\
pgpwde --recover --disk 1 (or if the secondary drive ends up being disk 2 try that) --passphrase "password" (or you can use --wdrt "wdrt here" if you have an managed client and a whole disk recovery token)
to tell which disk it is you can try:
pgpwde --enum
Then find the disk not listed as C:
This will force the Encryption Desktop application to scan the whole drive sector by sector searching for the backup records to unlock the disk.
If it manages to find it, it will notify you and then you will need to re-attach the drive again and authenticate at the PGP passphrase prompt (in Desktop)
At that point, I would recommend copying the data before attempting anything else on the disk.