Dear Srini,
Usually this might be an issue with Role assignment. It only works if the iView which is registered to this operation is available in one of the roles assigned to the user. In this case the 'qte'.
Please check whether the iView 'com.sap.pct.srm.core.iv_display_rfq_qte_resp' has been added to
the roles that were assigned to this user.
If you are using custom roles for administrator, could you please test if you get this error if assigning the standard SAP role to this user ?
Best regards,
Tamas