The conversion of the project was successful.

The new directory structure is as follows:

E:/Desktop/Power Electronics-Converters, Applications and Design - MEDIA DISK/PSpice-based Examples/PE_PSpice_Files/1
    DBRECT1.opj
    dbrect1.dsn
    dbrect1.dbk
E:/Desktop/Power Electronics-Converters, Applications and Design - MEDIA DISK/PSpice-based Examples/PE_PSpice_Files/1/DBRECT1-PSpiceFiles
E:/Desktop/Power Electronics-Converters, Applications and Design - MEDIA DISK/PSpice-based Examples/PE_PSpice_Files/1/DBRECT1-PSpiceFiles/SCHEMATIC1
    DBRECT1.sim
E:/Desktop/Power Electronics-Converters, Applications and Design - MEDIA DISK/PSpice-based Examples/PE_PSpice_Files/1/DBRECT1-PSpiceFiles/SCHEMATIC1/DBRECT1
    DBRECT1.mrk