Adding parameter in custom WEBADI

Hi Experts,

I have created a custom Web ADI to download and upload data in R12.2.6 version. As per Business requirement, I need to restrict the data downloaded with the use of parameters in sql query. Therefore, I created one parameter List having a String parameter type and passed the same to content SQL query as $PARAM$.param_name. But when I am trying to create the document it is giving error saying "Error" and nothing else.

Please let me know whether it is the correct approach to achieve business requirement. If yes, then how I can resolve above issue. If no, then please suggest me how I can achieve this.