Failed_Pinging_URL error

Hi All,

I am trying to install HP ALM 11.50 version, while configuring  PC server in lab Management reveived that error,I am confused on internal and external URL’s to be provided.

 I have Just enter the machine name and clicked on tab button, it is populating automatically the internal and external URL's as http:// machine name.But when I click ok button it is showing me the following error message.

Failed pinging URl .

Can anyone please help on this? 

Thanks,

Shiva Gangadhar