need help with a Ambiguous reference 'constructor'

This code is generating a Ambiguous reference ‘constructor’ error and I am unsure how to fix this.

var serialLightSource1 : SerializedObject = new SerializedObject(target.dynamicLightsource1);`

SerializedProperty takes an object (of type Object) as parameter. There is no such property as dynamicLightsource1 in a instance of class Object. Therefore you need to perform a cast first.

Try this solution (here I assume that your script if of type Script):

var targetDynamicLight : Light = (target as Script).dynamicLightsource1;
var serialLightSource1 : SerializedObject = new SerializedObject(targetDynamicLight);
var serialProperty1 : SerializedProperty = serialLightSource1.FindProperty("m_Lightmapping")