Error in for loop

I have this for loop:

for (var i in jsMonsters) {
    Debug.Log(jsMonsters[i]);
}

Which gives me this error message:

InvalidCastException: Cannot cast from source type to destination type.

Can you explain why that is happening?

Thanks - Elliot Bonneville

Also, so I don't have to edit my Question with more information later, here's what populates the array:

function ReadFile () { var sr = new StreamReader(Application.dataPath + "/" + readFilePath); var fileContents = sr.ReadToEnd(); sr.Close();

 var monsters : String[] = fileContents.Split("-"[0]);

 var jsMonsters = new Array(monsters);