How do I stop my games from corrupting on my DSL?

How do I stop my games from corrupting on my DSL?

My boyfriend got me one of those R4 things. It says “dstt” on the front (website: www.Ndstt.com).
Anyway, just about every ROM I play corrupts at some point. All my pokemon ROMS (diamond, platinum, pearl, and JAP versions of HGSS) corrupt within 2 hours of gameplay (Platinum has coped the best – it only corrupts the “last save file”, so I just save twice before turning my DSL off).
It’s not just pokemon games, Style Boutique (aka Style Savvy) corrupted after 600 customers.
I haven’t played any other games long enough to discover whether ALL games would corrupt.
I want a way to fix it, so don’t tell me the solution is to “buy the real games”. I have Diamond and Platinum as “real games” already.
I just want to be able to enjoy a ROM of a game (before I go out and buy it when prices go down a bit) without it corrupting.