Hi Prem,
The dump is saying that the function module ZOM_ZRET_WCOUNTRY_UI_INIT is not found which is an custom function module. Just create this function module and try once again.
OR
Try to remove this function module call from the standard report.
SAPLCOM_PRODUCT_DETAIL_UI_2 is the report from where this function module has been called, put the debugger and remove this function module call.