If you are the administrator then try the admin / master password used during installation.
Else, check with your administrator/basis team. they will be able to provide your the password. Else, reset the password using the following Wiki: SAP Community Network Wiki - Portal - Reset SDM Password in Unix and Windows Environment
or Document
http://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/c02a3c27-ae7b-2d10-3b90-c03a15...
Regards,
Sharath