I am also getting PGPError #-1. I have Mac OS 10.8.2 and PGP Encryption Desktop 10.2.1 MP5. I have been able to encrypt the drive that holds the operating system, but have been unable to encrypt the second drive that is empty. This second drive has been previously encrypted but has been unencrypted and erased and repartitioned. After receiving the message I also reinitialized the drive with Drive Genius 3 and further confirmed that this second drive does not have PGPWDE files on them. I then tried to instrument the drive with PGPWDE terminal command and get another error:
> pgpwde --instrument --disk 1
bootinstaller failed (49154): No such file or directory (0:3:2)
Failed to prepare for encryption
Operation instrument disk failed:
Error code 2: PGPClientError #2
It appears that PGP Drive Encryption cannot "instrument" the drive and is producing PGPError #-1. However I cannot even get PGPWDE terminal command to instrument the drive either.
I have been through TECH198399 doc and have not solved the problem.