ImageMagick directory path does not work

I just started with Omeka on a hosted webspace.

Testing the ImageMagick directory path is followed by the warning:

The ImageMagick directory path does not work.
Warning: realpath(): open_basedir restriction in effect. File(/usr/bin/convert.im6) is not within the allowed path(s): (/srv/www/vhosts/archivinfo.ch/httpdocs/:/tmp/) in /srv/www/vhosts/archivinfo.ch/httpdocs/omeka/application/libraries/Omeka/File/Derivative/Image/Creator.php on line 250

The provider won't change the open_basedir restriction. Is there any othe possibility to resolve this?