Ok, its just that the maps use up to date melee information, and I suspect that you are not using the most recent patch, so you can't play it.
So you can either download the most recent patch (Patch 1.24d)
OR
Open the maps individually and change the following setting:
Scenario -> Map Options -> Game Data Set
And change it to: Default (based on melee map status)
Tell me if you have anymore probs!