before trying to bounce again, you have to delete the target bounce tracks, 7/8 and then delete unused again. if you have exactly 5 mins per track, then you have 6 x 5 = 30 mins. then add 2 for 10mins and you have 40. so it should fit. but if you have 5 mins and 30 seconds per track then you have used up 3 more minutes with 33 mins used on 1 to 6. should still be enough room. make sure you have no other songs in the memory, or any stereo wave files you converted in the 2mix directory. there could also be leftover files somewhere on the card. check the contents with a pc and see if there's some other fragments on it. if there are, then upload the song you are working on to pc, make a backup copy of that on anohter pc or a cdr or another directory or someting, then re format the card and download the song back to the chip. I'd only do this if you've tested that you've done it before though. Also, even if one of your tracks is over 5 mins and you've erased some of it, a lot of it, or a piece or some of the end, the part you've tried to erase doesn't return back to free memory pool. it stays there on the track, the track isn't reset to the new ending.
BTW, what does it say when you arm a track? how much time is left? whatever it says, you have to divide by 2, of course. so hopefully when you've made sure you have room, arm and it should say 14 minutes remaining or something like that. 7 per track.