The Database and the File Browser are completely separate...and should not be confused.
If you launch playback with the File Browser, pressing Select in the WPS will take you to the current tracks location in the File Browser, if you launch playback with the Database pressing Select in the WPS will take you to the current tracks location in the Database.
This has nothing to do with the Database except for the fact that until now you've obviously not been using the Database as it hadn't been initialized.
If you continue to use the File Browser, even after initializing the Database, it will still function as you expect.
[St.]
EDIT:
Since you asked though (although it is not necessary to do so in this case), to revert the player to the state it was in before the Database was initialized simply delete all the files with the extension ".tcd" in the .rockbox folder on the root of your players disk and reboot the player.