Microelectronic Circuits SEDRA/SMITH Multisim
Why PSpice problems were created to different exercises comparing to Multisim files?

At first, I do not understand this question. Where are problems created ?

Secondly, I would not recommend to use the existing files on CD. The larning effect is rather limited because you do nothing else than to run some existing files and programs without knowing what`s really going on. 

Instead, I recommend to create your own simulation profile based on the examples given (circuit diagrams and/or small signal equivalent diagrams). So you can - for example - switch between real and idealized opamp models and evaluate the differences.