If the password for the <SID>adm user is correct then possibly it could be due to wrong domain. What does the event viewer log say?
Try this. Connect to the server with an Administrator user and create a batch file (Eg: sidadm.bat) with the content
runas /user:hostname\sidadm cmd.exe
Note: Replace hostname with the correct hostname and sidadm with the correct user.
Run the batch file (double click) and when it prompts for the user password enter the password for the sidadm user. If that works then follow the SUM guide to start the SUM tool.
The SUM guide says you need to "enter the command <DRIVE>:\<update directory>\STARTUP.BAT"
Cheers
RB