Plugin wptouch does not work

Hi guys I need your help.

I installed wptouch and I get on my blogsite http://blog.guntmarwolff.com the following error:

Warning: Cannot modify header information – headers already sent by (output started at /www/htdocs/w010930a/index.php:3) in /www/htdocs/w010930a/blog/wp-content/plugins/wptouch/core/class-wptouch-pro.php on line 406

What am doing wrong??

Thank you