>I have a toolbar called mytoolbar in a classlib called myclasslib
>I want to make my toolbar invisible.

It doesn't matter what is class name and even library name. However it does matter how you called the object (name property) instanciating from the class. This name should be used in reference, e.g. if toolbar 'tbMain' is part of formset, you use Thisformset.tbMain.Hide