i cant get nero to burn the image of this DVD-R...

i got a DVD-R movie, and i made an image.. its like 4.2 GB.. then i try to burn the image onto a DVD-RW and it says not enough space???

DVDr's dont play well on my dvd player so i need the RW... but this wont work at all... i got the phillips burner... am i doing sumthin wrong?? or do i need to rip the movie too????