[horde] cannot connect to databaes

[Mike Poznecki]

Hi, I have the following code in my new private function:
global $injector, $registry;
$sparams = $injector->getInstance('IMP_Contacts')->getAddressbookSearchParams();

Which I copied directly from another existing Horde page.  When I run it, I get:
PHP Fatal error: Call to a member function getInstance() on a non-object
I have tried many things but cannot get this to work. Can someone tell me what I am doing wrong?