Data Protection Manager Database Backup fails with Invalid Command

From time to time you need to backup your DPM Database manually. I used to simply run the command

DpmBackup.exe -db

But when I tried now I only got the error

Error: Invalid command -db.

There are a lot of posts out there covering this issue, telling you should include the -instanceName Parameter in the command but this didn’t help me at all.
After a while I added some more parameters and finally I found the following working for me:

DpmBackup.exe -db -sqlServerName localhost -instanceName MSDPM2012 -dpmDbName DPMDB