Hi Faheem,
You have not mentioned the Infoarea and Infocube name in authorization object S_RS_COM. Please add info area and infocube name based on which your query has been created.
There are Two Ways to add query in role menue.
1. Add URL by Go to Role(pfcg) - > Change mode -> Click on "Other" in Menu Tab - > Select SAP BW Query URL - > Enter URL and description -> Save
2. To add a query -> run RRMX or BEx Analyzer -> Open dialog to Select Query -> Search Query -> Select Query -> You will have a button in the dialog box "Enter in Role". Click -> another dialog appears with Roles. -> Select Desired role
For point2 prerequisite is that you should have access to edit role via object S_USR_AGR in any role and The role where you want to assign query should be assigned to you in Su01.
Thanks-
Guru