SharePoint Client Object Model: How come I cannot update other columns (fields) in my SilverLight App

I need help.  I am trying to update the columns (fields) of a list item.  I am working on a Silverlight Application that will be hosted in a Silverlight Web Part.

Here is my code:

If I comment out line 212, it works perfectly and updates the title column (field) but I want to update the "AnotherField" column (field), or any other I may want.

What am I doing wrong? It doesn't throw an error either.