Hello Varun,
This situation is coming because you have not detected and set up context at your Universe level and whenever this happens you will be prompted to select the appropriate path to execute the Query.
In order to avoid this you will need to explicitly set up and define the Context path so that it does not gets prompted to end user instead will will make the Universe smart enough to detect appropriate path based on objects selected.
For detailed information on how to detect and resolve please refer to below links
If your Universe is on 3.1 Universe Designer refer to below on page 227
http://help.sap.com/businessobject/product_guides/boexir31/en/xi31_designer_en.pdf
If your Universe is on IDT refer to below on Page 142
http://help.sap.com/businessobject/product_guides/boexir4/en/xi4_info_design_tool_en.pdf
Regards
Niraj