Is anyone else having trouble with completing the quest? The quest helper says I have five out of 5 daruma in the field but when I return to town it says I only have four out of five daruma.

Not positive, but I had the same problem and it -seems- to be that you have to kill the Durumu's completely on your own. I only managed to kill 2 without anyone else showing up to 'help' (*cough*), and when I got back to town I had credit for 2/5. So while it's not a guarantee, it's something to consider.

*Prolly does not apply to parties