Navisworks exporter error in Auto CAD MEP 2013

Hi experts,
I have installed AutoCAD MEP 2013 and after a clean installation I received error message. The error states: “Unable to load”. I do not know what happened so please help me to fix this issue as soon as possible. I hope you can suggest me best solution. Thanks. The error is given below

Unable to load C: AutodeskNavisInstallation
x64x64NWEXPORTAutodesk
SharedNavisworks2011nwexport2011nwexport2011.arx file.
