Import of Demo Data Fails

Hi there,
i´m trying to import the demo data.
In both ways
1. -> Theme Options -> Import Demo Data:
Import Error!
An error occurred during the import process.

This error occurs

2. while manual import:
Import WordPress
Medien “ishyoboy_kopy_logo” already exists.
Medien “blog_01” already exists.
Medien “blog_02” already exists.
Medien “blog_03” already exists.
Medien “blog_04” already exists.
Medien “blog_05” already exists.

i waited around 10 mins to finish the import. don´t think the web server would be that slow thats it takes more time.
I even tried before another manual import try to remove before the files in the upload folder.