What the?!?!?!

Can someone PLEASE explain this to me? Makes NO sense AT ALL! I’ll walk you step-by-step what I’m doing and where I’m stumped.

Backing up my scanned comics to a DVD. Using Nero Express and clicking Make Data DVD. When I get to the next screen, Disc Content, I add my files from my D Drive which are correctly listed there in numerical order as:

Avengers v3 25 (440).cbr
Avengers v3 56 (471).pdf
Avengers v3 501.cbr

HOWEVER, when I highlight them and add them to the files to be burned, it appears as:

Avengers v3 25 (440).cbr
Avengers v3 501.cbr
Avengers v3 56 (471).pdf

WHY?!?! And how do I get them in the correct order? Tried a few options and nothing worked.

try to rename the Avengers v3 56 (471).pdf as Avengers v3 [B]0[/B]56 (471).pdf

i.e. adding a zero to all numbers; in this way the order should be correct