In a text I used several symbols of the "King Tut"-font, of the "King Tut Too"-font and the "Trlit_CG Times"-Font. These symbols are not converted in the PDF file. ?

Having gone through this thread and now understanding that the OP is using Reader along with the “PDF Pack” that provides an Adobe cloud-based conversion service for creating PDF from Office documents, some observations:

(1)     As pointed out, this web conversion service only provides access to some Windows systems fonts as well as fonts from Adobe. There are many, many fonts that are not available with this service and you will get substitutions for fonts that aren't available. The results of such substitutions are (a) the text will look different in terms of style because the substituted font has a different design, (2) there will potentially be different line, paragraph, and page breaks due to different font metrics in the substituted font, and (3) for characters that are not in the Western Latin character set, especially symbolic characters, it is possible that you will get either blanks, a .notdef character (i.e., the box with an X through it), or some other unexpected character.

(2)     The web conversion service cannot deal with graphics that are not fully embedded in the Office document. For example, if your Office document uses links for graphics (strongly recommended for graphically-complex content), such linked graphics are not detected and uploaded with your Office document for PDF conversion. As a result, you will end up with blank space or an error message wherever you expected one of those linked-graphics.

(3)     There is no access to the .joboptions that are available to control the parameters for PDF creation when such creation is done on your desktop. The web service does not produce an all fonts embedded, high print quality PDF file. There are no color management controls.

Bottom line is unless you want good-enough for casual desktop use PDF from simplistic Office documents that use Microsoft Windows system fonts, the web-based PDF creation service is probably insufficient for your needs.

          - Dov

PS:     As far as I can tell, the same thing is true for any other web/cloud-based PDF creation tools.