DVD ISO works after burning not works ?!?

[Stiffler]

I have a problem i try to make DVD with chapters etc... in DVD MF2
then i burn it as ISO file to my HDD...
i try to mount it with Clone Virtual Drive, next PowerDVD player runs and plays DVD (iso) correctly... everythink OK
i think it's fine so i burn it with Nero Burnning Rom with BURN DVD IMAGE option...
after burning, DVD doesn't work in PC DVD-ROM not even in set top player...
when i try to play it with PowerDVD player it shows me an error message:

This DVD title's file format is invalid.
ERROR 81200016

what is wrong?
is it error in Nero or in DVD MF ?

thanks a lot.