[Solved] Invalid file extention - problem

Hello everybody

I installed CKEditor 4.4.3  and CKFinder 2.4.1 (PHP version for use with Webyep). Works ok, but I got one last problem. When I try to upload a file (e.g. PDF) I always get an "invalid file extension." error. Image upload works fine (bmp, gif, jpg...).

I played with the settings in the ckfinder/config.php file to see what happens. This is what I found:

- First of all: I use the default settings => "pdf" is in the allowedExtension and the "files" folder exists at the right place ($baseUrl = '/webyep-system/daten/userfiles/'; / Full write permissions 777). 

- When I add "pdf" to the allowedExtension in the images section, I can upload a PDF into the images folder. Nice, but not what I want. I like to have the PDF in the "files" folder. 

- Then I realized another thing: The filemanager only shows "Images" and "Korb" (Basket). But where is the "Files" folder??

Could this be the problem? Something wrong with the "Files" folder?

Thanks for help!
Dave