ORCAD 10.2 转NETLIST,请教该如何解决？

ORCAD 10.2  转NETLIST出错如下:

Netlist Format: pads2k.dll
Design Name: F:\PCB\1992\715T1992-A.DSN
ERROR [NET0018]   Design is not annotated.
ERROR [NET0011]   Netlist failed or may be unusable.

请问是什么原因,该如何解决?//