Open Crystal Report from a file server/ network on web server

I have a web server where an ASP.NET 4.0 site is hosted in iis 6.0.

I also have another file server (internal server & on a different domain) with some crystal report files.

The web site has a page which opens crystal report from file path of the file server & displays the report via the crystal report viewer control.

The problem is when i run the page, I get this exception :

"Unsupported Operation. A document processed by the JRC engine cannot be opened in the C++ stack."

Some solutions for this issue say :

1) Crystal Report File should be copied to the same folder where site is hosted which i cannot do.

2) Check for appropriate file path & permissions.

I can verify by logging remotely into web server that file server is accessible & appropriate permissions to read files are set.

I also verified that crystal reports can run on web server by creating a winforms app which runs same reports.

Please advise what am i missing & how do i go about diagnosing this issue..

Thanks In Advance..