I can’t get SavSend to work for everyone: Im unable to reproduce the problem; it works fine for me.
But as someone asked for it, here is the sourcecode. Compiles fine on devkitpro R21. It only makes use of libnds and libwifi~
http://n00bey.bplaced.net/?p=112

SavSend is a homebrew created by n00bey. That allows you to backup your genuine games cart's SRAM by sending it to your computer via wifi and an internet browser.