Yes it’s OK now and I will go on with bbPress.
Thx for your support
Only for your information:
I am able to rebuild the error.
I’ve reinstalled WP step by step and I’ve check the function after every step of the configuration. I think the error is based in the bbPress Forum plugin.
All plugins are installed as in my first installation and the forum plugin is working fine.
The problem will appear only if you do the next steps over the WP backed.
I started my first Forum entry. After this I’ve added the first Topic. All is working fine.
Now I add my first Replie without a title and the error occurs.
Cheers
Normen
I’ve deactivated all plugins and I’ve used the default theme Twenty Fifteen.
And also a reinstallation of the bbpress plugin didn’t solve the problem.
Thx in advance for your help.
Normen