Re: Why does this cause the script to die?

["Thiago Bastos" <hellraider@...>]

>lua_register(luaVM, "WriteByte", l_WriteByte)
>
>and calling it in the script as
>
>WriteByte(0x453121, 15) <---made up hex

AFAIK, Lua doesn't support that numerical constant notation (0x for hexadecimal).
Your script isn't even compiling. Next time look for compilation errors.

You'll have to convert your numbers to decimal, or make your own hex2number() function receiving a string "0x453121".

Straight from the manual:

Numerical constants may be written with an optional decimal part and an optional decimal exponent. Examples of valid numerical constants are 

       3     3.0     3.1416  314.16e-2   0.31416E1

+Thiago Bastos