Microsoft OLE DB Provider for ODBC connectivity failed

Hi,

  I have installed Oracle 11gr2 client and configured the ODBC to access the Oracle Database from sql server 2008.

  Linked server creation failed with the following error.

Error Details:

Cannot initialize the data source object of OLE DB provider "MSDASQL" for linked server "DMTEST".
OLE DB provider "MSDASQL" for linked server "DMTEST" returned message "[Microsoft][ODBC Driver Manager] Invalid connection string attribute".

OLE DB provider "MSDASQL" for linked server "DMTEST" returned message "[Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified". (Microsoft SQL Server, Error: 7303)
   

     Kindly provide the solution for this issue.

Regards

Sheik MD