Each of the scripts applied to a land will have a different solution. You will need to name one particular script that is having problems. If you're trying more than one and seeing the same problem, provide the individual names of one or more scripts. Or, you may also name the download from this site.. for instance the "A Generic .CHL file" download.
One possibility.. some scripts require the land to have at least one town that is assigned to player 0. In the landscape editor, make sure there is at least one town assigned to player 0.
-ego533