Hi Wilson,
In general during the disk encryption process, it is not recommended to divide the disk into two volumes. Now you must try to decrypt your entire disk. Please try with pgpwde commandline tool to decrypt the disk. You will find the instructions in the KB below:
http://www.symantec.com/docs/TECH149110
If you have any questions with pgpwde command line, please let us know.
Best Regards,
bipshr