小弟ORCAD剛入門，在仿真教程中一個數字邏輯電路時出現了“
ERROR -- Digital simulator not present”這樣的問題，向高手求教。

**** INCLUDING test2-SCHEMATIC1.net ****
* source TEST2
U_DSTM2         FSTIM(1) $G_DPWR $G_DGND N07825 IO_STM FILE="HADD.STL"
$
ERROR -- Digital simulator not present
+  IO_LEVEL=0 SIGNAMES=B
X_U11A         N07820 N07825 SUM $G_DPWR $G_DGND 74132 PARAMS:
+ IO_LEVEL=0 MNTYMXDLY=0
U_DSTM1         FSTIM(1) $G_DPWR $G_DGND N07820 IO_STM FILE="HADD.STL"
$
ERROR -- Digital simulator not present
+  IO_LEVEL=0 SIGNAMES=A

所有設置都是參照教程完成，不知錯在哪里？