Upload problem when mixing images and PDF file

[eluser]LuckyFella73[/eluser]
In my first test I first called both image callback functions
and then the pdf callback function. When I call the pdf callback
function first, I get the same error message like mentioned before
just for the images and not for the pdf file anymore.
So I thinks that I have to reset the configuration in any way?
It doesn't seem to work to just set the config values in each
callback function.
Is there a way to reset the config values?