Hi Ritu,
Try this steps
First delete outbound delivery number.
Also check material has already been assigned below WBS-element->Activity.
Now go to CNS0.
put Wbs-element and click on components.
System will generate new outbound delivery number against new reser. number in cj20n
Now do VL02N based on new number.
System will now allow to post POST GOODS ISSUE.
try it I am sure it works , let me know
Thanks
Rahul