I found out what it was... here's the instructions when you install:

During the installation process the file config/db_settings.php has to be overwritten. Therefor you might have to change the write permission of this file. You can first try it without changing the write permission, if you get an error message try CHMOD 666. After the installation you can set it to 644 again.

The directory templates_c has to be writable by the template engine. Therefor you might have to change the write permission of this directory. So if you get an error message try CHMOD 770 or 775.

Normally you can CHMOD files or direcories with your FTP programm (right click on file/directory --> CHMOD or similar)

In my case, I had to adjust the templates_c file before I got started in order to run the install...

Hope that helps anyone else with the same issue...

Julia