Do so how you normally would when playing the GBA game on a GBA (It best be a GBA game, because DS and DS Lites cannot communicate to older Game Boy games), go through the menus (on the game) and delete the files. It's not a matter of the DS having the problem it's the game.
I've went through the menu's and deleted the game but my game still has "corrupted data":
First, do all you can do, clean out the slot in the DS Lite, and the cartridge (with a damp, NOT SOAKING WET, cotton swab), and try the game again. Start a new save file, save it after a ways, and try to load it again. IF it -STILL- has a corrupted save file problem, then it is time to bring it to the seller or the manufacturer.
The seller: Telling the seller what's happening is great. BUT SHOWING the seller that the save data never loads really helps! Customers can say quite a few things to Sellers just to get a new game or their money back, but showing them is pretty much proof. No, you don't -HAVE- to show them, but if the seller is -that- skeptical, it may be wise to bring your DS along with you.
The manufacturer: All games have a Technical support call number, also going to nintendo's main site,www.nintendo.com/
, and going straight to their technical support pages helps too. Sending it in will warrant a little wait time, but if done correctly you will receive a fixed or new game from them as well.