How to make new weapons?

I am trying to program a new weapon. I have made a new .qc file and add it to w_all.qc. Write a w_weaponname() function and add the wepaon with REGISTER_WEAPON(). The weapon do currently nothing and has no model too because i want to bring xonotic first to working with a new weapon. But when i start the game with the new progs.dat the server/game crashes with some errors in the console. So what i must do more to bring the game to working?

You need to compile the client side code (csprogs.dat) too.

csprogs might be the issue, yes.

But really, if you get a crash, there is no general way we can guess why it's happening. Post the crash log and the code.