i have tried this
Start Registry Editor by typing regedit in Run window
Select the following key in the registry: HKEY_LOCAL_MACHINE\SOFTWARE\ODBC
On the Security menu, click Permissions.
Grant Full Permission for the account which is being used for making connection .
Quit Registry Editor.
Also tried this: ERROR : [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified
and also tried this: http://support.microsoft.com/kb/306345
but not get solution......