Facing difficulty to pass label value into listview

Hello
What i am looking for is to get the value of " Label10 "  which is into viewmsgView and then bind the FormView1 depending on the label value, Note: viewmsgView  &  FormView1  are located into same view and in same page. But i am getting an error message as below and i have added find control because it give error message that control is not available or does not exist. 
The parameterized query '(@UID nvarchar(5),@mailno nvarchar(4000))SELECT * From mails whe' expects the parameter '@mailno', which was not supplied.

viewmsgView  which include Label10 and as well the titlehyplink which when user click on it will show and bind FormView1 
<asp:ListView ID="viewmsgView" runat="server"> <ItemTemplate> ...