"Unable to get Match property of the WorksheetFunction class".

The below functinality works fine when the workbook has 1 sheet
but with more than 0ne sheet i get error on
Application.WorksheetFunction.Match


i have datavalidation list coded from VBA , this list is populated with data from database
i need to find the index no of the item selected in the list

with one sheet things were working without error but trying with multiple sheet i ge error
"Unable to get Match property of the WorksheetFunction class".


have used the functionality from the below link in thisworkbook

http://stackoverflow.com/questions/8...-dropdown-list
i tried
Application.Match - but i get type mismatch error