I got it working, thanks. It was a setting in my FTP:
Report external IP in passive mode 
Greets
1 2014-09-30 07:55:09
Re: Problems with FTP - Does not upload (2 replies, posted in Dropzone Support)
2 2014-09-26 07:28:50
Topic: Problems with FTP - Does not upload (2 replies, posted in Dropzone Support)
Hello Dropzone Support,
i have a problem with the FTP Upload. I enter all my details and click on Test connection. It works.
I save the ftp Upload and drag and drop something on it. It says uploading but nothing happens.
I wait a while and then i get this error:
FTP Upload Error
Operation timed out - connect(2)
Nothing has been uploaded. My FTP works with any other program.
Also the ftp upload seems to have a problem with Umlaute like äö etc.
Greetings and thanks for your help