No, not the plugin, but the GA from the GA homepage (you know: register yourself and then you get an account and a source code which you have to copy into the page you want to follow).
First I copied the GA source into the index.php file. But before that I backuped the index.php - just in case. Unfortunately afterwards I modified some posts from the dashboard, so the dashboard info did not correspond to the blog any more, and since that time my blog is dead.
Later I restored the old, backuped index.php file, but due to the modifications which I had made in the dashboard it did not correspond to the dashboard content, either. I don't know if this is the problem or something else, but surely the restore did not help.