. . . . a window pops up tell me it's wrong format . . . .
Does it give you the option to convert or continue?
Also try doing a program reset - File, Settings Reset . . .
. . . . but in places the image stopped running.
I have bought some Verbatim dvd to reburn. . . . .
I would suggest you get some rewriteable DVD-RW discs for initial burns then, as you have discovered, if there is a problem you can reuse the discs instead of creating coasters - saves money!
Once the movie on DVD-RW is OK use a program such as Nero, Roxio or ImgBurn to copy the DVD-RW to DVD-R's rather then trying to burn again in MEP.