blank page when child theme activated

I tried to customise esplanade by creating a child theme but when I activate the child theme, a blank page is displayed. I have to change the stylesheet option in database to reaccss the website.
The child theme cantains only a style.css with the following content:
@charset “utf-8”;
/*
Theme Name: PROCOMA
Description: PROCOMA Child for esplanade
Author: Fabian Fischer
Template: esplanade
Version: 0.1.0
*/
@import url(../esplanade/style.css);
The child theme is located in wp-content/themes/procoma.
The esplanade theme is located in wp-content/themes/esplanade.
Both templates are readable by webserver.

I am using esplanade 1.0.7.
I tried updating to 1.0.9 but after that the website does not work anymore.
I have seen an single colored page without any content.
Admin screen works except of the config site for theme header.
I tried reinstalling the template, too.
I used backups to go back to old version.