Yes, but the problem persisted. It is related to hosting WordPress on any server other than WordPress.com. I have had this problem since more than a decade and will now give up to host my sites and pay for hosting (which is so faulty for WordPress, including all the maintenance you have to do, while on WordPress.com all is automatic and no maintenance needed).
Please close this thread.
Best regards,
Peter Fritz Walter
Sorry I had to change my profile because of a password reset. So my answer to the question is here:
http://creativeself.org
In the meantime I have changed the theme but found out that I still receive HTTP Error and cannot upload images to my WordPress blog. I wrote to the server support now.
I found on forums this may be related to the wrong PhP version or wrong htaccess settings. If you happen to know, kindly tell me. Thank you!
