Hi,
You can reset the password for OMS to default (oem_temp) by the following:
1. Shut down the OEM console login dialog box.
2. Shut down the Oracle Management Server (OMS).
3. Connect to the repository database as the repository owner using SQL*Plus Worksheet. Chose the option to "connect directly to a database"
4. In SQL*Plus Worksheet, click on the menu item File, select Open.
5. In the file Open dialog box, navigate to the <OEM 2.1.0 home>/sysman/admin directory (Solaris) or the <OEM 2.1.0 home>\sysman\admin directory (Windows 95/98/NT)
6. Open the file vduResetSysman.sql and then execute.
7. Restart the OMS and Start the OEM console.
8. Log in as the user "sysman" and specify the password "oem_temp". Change the default password when prompted.
Regards...