The conversion of the project was successful.

The new directory structure is as follows:

C:/Users/Behrooz/Desktop/SPICE Examples - Orcad New Version/Appendix B-PS.4
    Appendix B-PS.4.opj
    Appendix B-PS.4.dsn
    Appendix B-PS.4.dbk
C:/Users/Behrooz/Desktop/SPICE Examples - Orcad New Version/Appendix B-PS.4/Appendix B-PS.4-PSpiceFiles
    Example PS.4.1
