If you try alt-g again does the same thing happen?
If you place the caret into the call:
CPrintableDialog::OnInitDialog();
what does VA show in the context and definition fields?
As a simplified test I have just added the following code to a C++ header file:
class testAltGBaseClass
{
public:
	virtual void OnInitDialog()	{ }
};
class testAltGChildClass : public testAltGBaseClass
{
public:
	virtual void OnInitDialog()	{ }
};
class testAltGGrandchildClass : public testAltGChildClass
{
public:
	virtual void OnInitDialog()
	{
		// test alt-g on this function call
		testAltGChildClass::OnInitDialog();
	}
};
using VS2005 and VA 1618, and Alt-g takes me to the correct place in the header file.