Massive lag when game starts

[Jonnycakes]

I am working on a new map and have run into a problem that I haven't seen before. When the map is run through the world editor's test map function, it runs fine. When it is run on a LAN, there is a huge amount of lag. The framerate doesn't suffer, but when a player issues an order to a unit, it can be 10s of seconds or even minutes before the unit responds. After the initial wait, the lag isn't a problem. I have no idea what's going on-what could be causing this?

EDIT: Solved...