How to track error while executing Oracle report in oracle forms

Hi,

     While running Oracle report from Oracle Forms, when user wants a report from_date to to_date, It is sometime the  report get successfully runs, sometimes report shows blank and sometimes report not able to open due to some error , but we are not able to track the error in oracle forms.

We are sending this reports for approval from management. So, sometimes they are getting blank reports.

We want to track this unknown error while executing the URL. Whether it is successfully runs or not. Then only it will be sending for approval.

The URL link is :

http://winorasrv-pc:1002/reports/rwservlet/getjobid'||SUBSTR(x,y)||'?server=rptsvr_winorasrv-pc_asinst_1&userid='||:global.vusername