What's wrong with this code?

FASM CODE:

Code:

format MS COFF
include '%fasminc%\win32a.inc'
public _crypt
section '.text' code readable executable
proc _crypt, text:DWORD
lea eax,dword[text]
push eax
lop:
xor byte[eax],8
inc eax
cmp byte[eax],0
jnz lop
pop eax
ret
endp

C CODE:

Code:

#include <stdio.h>

int main() {
char *text="hello";
crypt(text);
puts(text);
system("Pause>nul");
return 0;
}

to build:
fasm crypt.asm
gcc -c prog.c
gcc prog.o crypt.obj -o prog.exe

What I'm trying to do is making a procedure in fasm to call from C to crypt texts. But it seems that I don't know how to get the address or something. Could you check this out for me, please?
Sometimes it gives me memory error and sometimes doesn't, but never works.

Thanks!