Generally speaking no, adding another profile to the disk should not make the first profile inaccesible. How many total profiles were setup?
And did any of these have the same username/password as a previous profile?
To regain access to the disk try the following:
run the following commands from "Program Files\PGP Corporation\PGP Desktop" to try and authenticate to the hard disk then decrypt.
To check disks of a system type: "pgpwde --enum"
To check the status of a disk, type: "pgpwde --status --disk <disknumber>"
To list users on a disk type: : "pgpwde --list-users --disk <disknumber>"
To authenticate a disk, type: "pgpwde --auth --disk <disknumber> --passphrase <passwordhere>"
To decrypt a disk, type: "pgpwde --decrypt --disk <disknumber> --passphrase <passwordhere>"
To recover if entering the passphrase fails, type: "pgpwde --recover --disk <disknumber> --passphrase <passwordhere>"