Hey sorry for the late reply. What version SM are you playing? After one of the updates (dont remember which one) The map stopped working altogether. I have read that after yet another update, the different maps were working again. I havnt played warcraft since mine began to not work with the new update. Itcould be that the map does not work properly in the new versions.
It has nothing to do with battlenet. As long as 2 or more people are playing it should work. (There were too many noobs playing offline in single player mode collecting all the kills and gaining xp faster, but when they played as a team on BN, they didnt know what to do.)
One day I may get the urge to install warcraft and try to fix whatever bugs there may be left. Starcraft II apparently has a converter to convert an old WC or SC map to the new SCII format. If it would work on mine, then I would port SM USA to a spacey version.