R4 theme problem

I have a problem with putting on a theme because when I try to change my theme on the DS, the usual message pops up that says "Manual Mode Theme ##" but the theme doesnt change it just stays the same as the one before.
the theme I'm trying to use is this : http://www.ndsthemes.com/themes/details/t/464fbd4ccf
I can't seem to use it but if anyone can and may be able to help me then please do so.

That's probably because the theme you want is for the Acekard 2 flashcart. Look for them in the R4/M3 Simply section.Or, you can simply use the 256x192 images from the Acekard theme, and overwrite your theme's images if you like them.

Oh ok thanks for the help, thought it was for the R4 lol