General Strange Error on Data Bound ComboBox

I have a combobox bound to a BindingSource, in turn bound to a DataTable of
Agent Names. Everything is handled by the VS 2008 designer, i.e. I have no
custom data binding code, nor do I have any code that sets anything on the
combobox. Yet, when I start my project, I get the following error.  This
only occurs when 'Break when thrown' is set for Framework exceptions, but
surely this should only apply to my code?  Is this maybe because I have the
ComboBox debug symbols loaded?





InvalidArgument=Value of '0' is not valid for 'SelectedIndex'.

Parameter name: SelectedIndex