Jump ends nowhere?!

This is probably a noob question... but I just don't get it...

I have a jump in the very first line that is executed according to
Bochs, but the code it then arrives at are just zero's (an empty part
of memory, not the jmp $ I expected). So something with my jump is
wrong, but why?


This is my code:

jmp RealMemModule_end	;Don't execute the code - it just needs to lie
around somwhere :P

AllocateMemory:
checkStackSafe 14
jc short .stackOverflow

o32 push eax
o32 push ebx
o32 push ecx
push si

mov al,byte[MemoryMap_start.mapSize]										;Use the map-size in si
as a counter
mov ah,0
mov si,ax

....large amount of code ...

times 0x200 - (MemoryMap_end - MemoryMap_start) db 0						;Make the
mapping area 200 bytes long

RealMemModule_end:
jmp $