Getting error on assigning custom bol to std component as assingment block

Hi Friends,

I have created zbol and tried to add this as assignment into standard component. for this is use below link.

http://wiki.sdn.sap.com/wiki/display/CRM/How+to+use+your+custom+BOL+Object+for+webclient+within+assignment+block.

at one place am getting error.

METHOD root_query.

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lrf_advanced_query = cl_crm_bol_dquery_service=>get_instance( 'Search' ).

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I couldn't  understand what is this Search, as i followed every steps, but nowhere i found step for this.

Note: first part of this document ( Create your own BOL Object ) is unable to open screenshots.

Thanks

RI