LT spice - error message - first time LT spice user

As a first time user, i am probably doing something dumb.  I am getting the error message: unknown subcircuit called in: 

"xu1 n003 0 n001 opamp aol=100k gbw=10meg " 

even though i have the spice directive .lib.opamp.sub placed in my schematic.  Why doesn't it find this library containing an ideal opamp?

thanks in advance