Delivery blocked the requirements

Dear All,

in my plant i have sufficent stocks to place an order and that order can be confirmed without any deviation from the quantity.

but now i am facing the issue with the order confirmation when order is created with the available quantity in the plant .

when i looked at the stock requirement list only partial quantity is confirmed and remaining quantity was blocked by the delviery document which was created way back in the year 1999.

all items in this delivery was already confirmed ,PGI is also done and billing was generated and cleared as well nothing is pending.

why this old delivery is now appearing in the stock requirement list?

how to remove this docuement from the requiremnt list?

please advice me.

TIA

KOGI