no it is because it's dsiware, i am not using an R4 but i saw the icons in the rom folder just like any other game but when i opened the game it didn't work
I'm a bit confused by your message, did you mean to say "no it is not because it's dsiware, i am using an R4 but [...]"?
Assuming you are actually using an R4 (or other flashcard) like you said in your first message, it being a DSiWare
is the problem. It's normal that it shows up because DSiWare are still the exact same file format as any other DS game, however they won't actually work on a flashcard because they expect to be run in DSi mode and that's simply not possible on a flashcard*. You'll need to install TWiLight Menu++ if you want to use DSiWare ROMs.
If you aren't using an R4 (or other flashcard), then how are you trying to run it? TWiLight Menu++? If so, then you may need to install Unlaunch as that improves DSiWare compatibility. If you've also already got Unlaunch then maybe try using
hiyaCFW, it has perfect DSiWare compatibility, however you should be fine with just TWiLight Menu++.
*technically it is sorta, if you install TWiLight Menu++ on both your DSi and the flashcard then a couple DSiWare can be sorta run from the flashcard, but compatibility is very low and its rather pointless as you need to have TWiLight on your SD card anyways.