Error in Webdynpro Abap application...

Dear Experts,

The following text is the error while i m trying to run my application... I m very new to Webdynpro abap.. So please help me on this... Also please tell me how to get the input from the user and how to display it in other view...

Error is:

The lead selection has not been set. MAINVIEW ￿ꯂＧ

Thanks.