No-Intro records change over time so I ran a fresh scan of the Nintendo DS Vault and found six games that don't match. I'll get on those later, but Dragon Quest V is No-Intro verified.
I'm curious why a No-Intro game doesn't work for you, so would you be willing to check the SHA-1 hash of the other copy you downloaded and see if it's on this page?. If you have 7-zip you can use it to find the SHA-1 hash.
When I played Dragon Quest V for the DS, I encountered an error where it was just a white screen. After downloading it from another website it now works. Just wanted to say in-case it's a broken file or something.