Insert NewRecord into BusComp -Siebel

Question

I am trying to insert some records into a BusComp once an applet that's using a different Buscomp has finished loaded. Below is my code

var boContact = this.BusObject("Contact");
var bcContact = boContact.GetBusComp("Contact");
var newBC = boContact.GetBusComp("New BC");
            
   with (newBC) {
            
   this.SetViewMode(AllView);
   this.ActivateField("Test Field");
   ClearToQuery();
            
   NewRecord(NewAfter);
   this.SetFieldValue("Test Field","0010000005");
   this.WriteRecord();
            
   }

Currently this code is giving me this error 'This operation is not available for read only field 'Test Field'.(SBL-DAT-00402) '. I have checked and confirmed that the said field or any other fields in the BusComp and the table are not set to read-only.

Please share your thoughts with me, thank you so much !