there were a lot of problems, it seems, with the first crop of maxtor hard drives. this has popped up here, and there was like four pages of it over at macfixit's boards. you should do a search and read other's experiences.
i got the 80 gig maxtor FW drive the week it came out (last october?). a couple of months later, it would stall out whenever I used it--just freeze up and crash the system (i didn't get the message you got, though).
i called up maxtor, and they had a new drive at my house within 7 days. i transfered all my files (which took a while because of the freezes) and sent it back. never had a problem with the new one--it's running excellently (just ran mp3's off of it for a 4 hour poker game).
do you have one of the new ones? you can tell by looking on the back--does it have a power switch? the original model had a power switch on the back corner. the new model has no power switch--you just unplug it to turn it off, plug back in to turn it on.
anyway, getting mine exchanged was real easy. it just cost me one way shipping charge of like 7 dollars. if this problem has persisted, i reccomend exchanging it (they have a no hassle policy.)
oh--but don't wait too long--my old drive stopped working COMPLETELY just after i got the last of my mp3's transferred. it was dying all along....