"critical error during upgrade process"?

Hi,

when I go to the piwik login I get the above error message. It continues:

Database usr_p30971_1 is empty. You must edit or remove your Piwik configuration file.

Of course, the data base is NOT empty, and the configuration file seems to be absolutely CORRECT.

I don’t know what to do with this. I did not do ANYTHING with the Piwik installation.

What does this mean?

What can I do?

Grateful for help
Stefan Padberg