Data not saving in MVC2 Edit_Post controller action

Question

My View inherits a strongly-typed object.

My Edit (Get) controller action returns a View, passing to it the model object.

When my Edit (Post) controller action accepts a FormCollection object, calling UpdateModel and db.Save() works fine. If I change the Edit (Post) controller action to accept the strongly-typed object instead of the FormCollection object, nothing is being saved and no errors are being caught in my Try/Catch block.

What am I missing?