moved my session onto a faster drive, but PTLE is still playing the old audio files

[heartparts]

i've been using an mbox with my 700 mhz ibook with it's internal drive for a while with very little problems. lately i've noticed some hiccups in my recording and i decided to buy an external 7200 rpm firewire hard drive. i copied a song and it's audio files that i'm working on from my internal drive to my external drive. now when i open the song file from the external drive i think it's still using the audio files from the internal drive.

how do i know this? well first of all i can hear my internal drive clicking away, just as it did when i was running the song off the internal drive. plus i haven't noticed any speed improvements.

is there something else i need to do besides just copy the files over?

thanks for any help.