Help with Set Analysis expression

[sai_katare]

Hi Team,

I am trying to do the following 2 steps in qlikview:

1. Take 'product number' as an input in the inputbox

2. Find the relevant 'Product Description'  using a set analysis expression  inside a straight table. But my set expression is failing. 

Expression:       =aggr(Only({<part_number={'$(=$(vInputPart))'}>}part_description),part_description)

Please help. I am getting 'Error in calculated dimension' message in the table column for this expression.