Object reference not set to an instance of an object. error getting while getting installing sql server 2008 r2 on windows server 2008 r2 sp1

Hi Team,

I am getting error while adding second instance to the same node while 1st instance installed without any error.

Object reference not set to an instance of an object. error getting while getting installing sql server 2008 r2 on windows server 2008 r2 sp1.

Please share if i am missing anything..

Santosh Singh