Multi and SP maps

[mapmaker]

I've made a few maps, and they work fine in single player, but when I try to load them up in multi-player, it says the file cannot be found, etc.

Does anyone know if you have to 'flip a switch' so to speak, before you start making a map, to get it to work in multiplayer, or am I missing something?

 

Thanks.

[mapmaker]

*bump*

I'm itching to start making a good map, but can't without knowing this, if someone could help me, please, I'd greatly appreciate it...