DraStic

I tried Dragon Quests 4, 5 and 9 and I only get to the start screen and I get an error about save file
9 tells me "The quick save log is corrupted"

4 and 5 said something about adventure log corrupted...

How can I get into these games?

It sounds like it's missing from the game database, or incorrect. What regions are you using, and do you know if the game has been patched, like for translation purposes?

US versions or EUR, same thing.

Exact message on Download Dragon Quest IV - Chapters of the Chosen (U)(GUARDiAN)

"The adventure log could not be saved. Please turn off the power OFF and reinsert the DS Game Card"

Have you tried any other games to see if they have problems saving? Are you using DraStic 2.5.0.3a?

I'll try this game later tonight, but it's in the database and it's unlikely that the save type is incorrect. You could have problems if there's something wrong with the game database, or if you're using a very early version that predates a large number of database fixes (but then you probably got it cracked from somewhere)

I have this 3 games tested. all are working fine

Aha I fixed it. I used Easy uninstaller to remove it completely and then reinstalled it and now I can open Dragon Quest IV just fine. Interesting