No, it is not possible to restore an Access Server password from a backup, nor does Symantec have a tool to extract the password.

If a pcAnywhere administrator changes the Access Server password, then it is necessary to update the host files for all host computers which are configured to dock to the Access Server.
Following are the most basic steps to update the host files:
 

1. Within pcAnywhere Manager (winaw32.exe), modify the host file with the new Access Server password.
2. Save the host file with the same name as is running on computers which are currently configured to dock to the Access Server.
3. Copy the new host file to each of the affected host computers.
4. Restart the Symantec pcAnywhere Host Service on each host computer.

Otherwise, to avoid the need to change the host files, revert the Access Server password to its previous value.