Hi Satyardha.
SPO_NUM is number range buffer for Spool requests. If the number range getting full, you use to get the dumps and error message as mention in the SAP Note 48284.
Number of spool request upper range is set default value set in the profile parameters rspo/spool_id/max_number you can check the parameter value in RZ11.
because of this your spool request are shows 99000.
Refer the SCN thrad - SPO_NUM V.S rspo/spool_id/max_number
Regards
SS