Check this directory path: aspnet_client\system_web\2_0_50727\CrystalReportWebFormViewer3\JS
You will find the
directory under the parent website that your virtual directory is in. The
directory contains subdirectories for images, html, css, and js. If the server does not have these directories or they are incomplete then copy these files from your local development server to recreate these directories and the files in your server.
For more information, have a look at following links:
Crystal Report Viewer Export & Print buttons are not working in VS 2008
Also please do search Google
] before you post any questions here in this forum.