can i import CAESAR II file to model that was created with CAESAR II?

What do you mean?

Are you asking about importing/adding an existing caesar file to another caesar file, yes you can. Use the option "include piping input files", just remenber to renumber all your nodes first as to not duplicate any nodes with other files.

i'm importing ceasar file first time into blank model (2008) throws error message - says error reading, corrupt file

for clarity i want to create cadworx model from importing CAESAR II file - i dont have problems exporting/importing CAESAR II file from models created with cadworx - thanks for replies

You're going to have to be more explicit in what you wish to do here.