MSP to cProject Import Error

I am successfully able to download a project from cProjects to Microsoft Project Client. However, the system is giving me an error when I am trying to import the same project in MSP client format that I exported to MSP.

The error says

"Internal ActiveX error; [0x800405ec] Project cannot open the file"

Any ideas on what could be the possible problem for this error. I have done the field mapping for both import and export.