I get "Object reference not set to an instance of an object"

I'm using a web service that populates some drop down lists, and depending of the selected values it will load some info in dynamic gridviews that is in turn added to each tab. Previously I was using "Page_Load" only, but now using "Page_Init" instead along with "Page_Load" further down in the code. Before changing I could run the page, but had problem with content disappearing after changing drop down lists within the gridviews (not the same drop down lists previously mentioned, because they are outside the gridviews). Now, on this line of code (inside Page_Load):
Panel1.Controls.Add(theTabCtrl.GetControl); I get the error: "Object reference not set to an instance of an object". What can I be doing wrong? Is it the "theTabCtrl.GetControl" that isn't recognized? And if so, why? My code is below. I have simplified it very much, because ...