As noted one can separate the file name from the file path.
There is also the URL property and the documentFileName property.
this.path;
/File-na1-03/userdata2$/[userid]/My Documents/Adobe/Acrobat/Acrobat11/js_api_reference.pdf
this.URL;
file://///File-na1-03/userdata2$/georg581/My%20Documents/Adobe/Acrobat/Acrobat11/js_api_reference.pdf
this.documentFileName;
js_api_reference.pdf