Cannot delete the target of an active script event

I am writing a script that uses threeview.

In threeview I add document names (node) and page numbers (item).

I added a button that when clicked adds selected document page to selected frames of the document.

I use "afterSelectionChanged" event which I added to the document. This event calls a function in which I want to place selected PDF document to selected frame.

This is the part of the function that is throwing errors:

var mySelection = app.documents.item(0).selection;

for(var myCounter = 0; myCounter < mySelection.length; myCounter++){          

          if (mySelection[myCounter].constructor.name=='Rectangle') {

                        try {

                                    mySelection[myCounter].place(g.doc);

                        } catch (Error) {

                             alert (Error);

                            }

          } else if (mySelection[myCounter].parent.constructor.name=='Rectangle') {

                        try {

                                    mySelection[myCounter].parent.place(g.doc);

                        } catch (Error) {

                                       alert (Error);

                            }

}

All the time I get the message “Cannot delete the target of an active script event”, even dough the

ev.currentTarget before place is [objectDocument].

Please HELP, I have no more ideas!!!