The conversion of the project was successful.

The new directory structure is as follows:

S:/WORKAREA/MANIP/Download/1
    Buck_CCM1.opj
    buck_ccm1.dsn
S:/WORKAREA/MANIP/Download/1/Buck_CCM1-PSpiceFiles
S:/WORKAREA/MANIP/Download/1/Buck_CCM1-PSpiceFiles/SCHEMATIC1