I have done some research on google and found the following solution to my problem.
- In IIS Administrative Console snap-in, right-click the specific Web server where the .pps file is located, and then click Properties.
- Click the HTTP Headers tab.
- Click on Mime Types button in IIS 6.0
- Click the File Types button in older versions of IIS.
- Click New Type.
- In the Extension box, type .pps, and then in the Content type (MIME) box, type application/vnd.ms-pps.
- Click OK, and then restart IIS.
To know more click on the link from Microsoft