recently I started to do some scripting with my camera. I made a simple hello world program in C, compiled it and sent it too my camera.
The camera's system is a very bare bones version of Linux. Running
./helloworld: line 1: syntax error: unexpected "("
I assume you compiled your hello world program on your 64 bit desktop PC using something like
gcc -o helloworld helloworld.c.
The resulting binary is meant for AMD64 architecture (think Intel 64 bit) and won't run on any other processor type. I.e. it is incompatible with the target system (= your camera) which uses the 32 bit ARTPEC-3 processor with a CRISv32 architecture.
This means that you must cross-compile your program for the camera's CPU. Check e.g. http://developer.axis.com/wiki/doku.php%3Fid=axis:compiling_for_cris_howto.html which looks like a very good tutorial on getting your first program to run on your camera.