Map sheet Rolling Hills #2 is not the same map as Rolling Hills #2 from the Grasslands Map Pack, and is likely misnamed.
Solution - Rename map Hilltops #2 as otherwise there is no such map sheet available.
Xotl: It was decided to rename the map in MP: Grasslands instead. Rolling Hills #2 in that set is now Rolling Hills #4; the Clan Invasion map remains as it is.