form  Principle_Investigator_Registry

{

    displayname  =  "Principle Investigator Registry"

    success message  =  "Data Added Successfully!"

    field alignment = left
    PIReg=investigators.Investigator_Registration[];

I've also tried these iterations.

PIReg=investigators.Investigator_Registration;

PIReg=investigators.Investigator_Registration

It just gives me 'Error modifying the page null'.