Exception has occoured in .htm page while testing a custom component

hello all,

I am new to CRM. I tried to create a custom component using BSP_WD_CMPWB. But I am getting exception in .htm of views while testing custom component. Please tel me that where i done mistake and exact procedure to create component.

Exception is:

Exception class :CX_SY_REF_IS_INITIAL Dereferencing of the NULL reference

BSP Application :ZCMP_CUSTOM

View layout : zformview.htm

Method : CL_02DBPTB8BDDWTFFCM2ND6U309A9=>_ONLAYOUT