Hi， Nikilesh
On PAM (product availability matrix), additional information column has a note to reminder checking note 1076022 for the entry MS SQL 2008 and WIN 2003 of PI 7.1. So it is important to check the note for additional information about product PI 7.1.
Note 1076022 says, you cannot use the Netweaver 7.1 installation package to install a new SAP system on SQL Server 2008 (R2). As a workaround, you need to install on SQL Server 2005 , apply the required SAP_BASIS and SAP_BW support packages, apply a supported SAP kernel and then upgrade the database release to SQL Server 2008 (R2).
I am afraid there will be a lot of unexpected errors in the coming processing because the current scenario hasn't been tested and supported. So I suggest you following note 1076022's instruction to re-install the PI 7.1.
Best regards.
Cherry