Hi Alexander,
I believe I had also faced similar issue which was fixed by using Resolve.
Try something like coll = $controller.Resolve('/Root/DataList')
Incase if you are looking at the value of FamilyName in current record for which this script is running you can also write fname = $controller.Resolve('/Root/DataList/FamilyName') and it would get the current records F Name.
Also check if the name of your collection within Datamodel is Datalist or it is renamed by any chance.
Regards
Vinod