In between I have tried to solve the problem on one of my two websites, but I had no success. Things got even more worse than before:
First I deinstalled PDF component ans plugin. Then I cleared Joomla caches and then I had a look in the database, wether there would be some PDF related data. But there I did not find something. So I left mySQL database unchanged.
Next I have controlled ACE SEF, so that nothing could disturb the Phoca-PDF generation.
Then I reinstalled the Phoca-PDF plugin. No problem. It was deacticated and I let it in this status.
Then I reinstalled Phoca-PDF component. I got error message (in German, here I try to translate it in English):
error: The chosen installation format (client=both) is outdated. Please do use a packet installer!
information: Language Installation has been stopped: unknown type (both)
But in the administration of the extensions of Joomla, the component showed up and seemed to be active. So I tried to deinstall this component, but Joomla showed up the next errors, telling me, that there was no component in the path and even there would not be a XML-file for deinstallation.
Then I had a look via ftp and I did not find any Phoca component installed, neither in backend nor in frontend.
Then I checked mySQL database again and again I did not find anything PDF related there.
It is strange, that the updating process of Phoca-PDF yesterday was successfull immediately and now it makes trouble!
I tried to overinstall the component again. Then Joomla told me:
error: the installation of the component did not create any error message
info: error on component installation
I have no good knowledge about Scripts PHP server and all that stuff. My main business is health-related and psycho-social ambitions. So it might be, that I have forgotten to look at the right things in my database.
You will get website admin access within next minutes! Thank you very much for your offering of help and assistance!