Error in comment function of this blog

Checking the logs is an important work for web administrators, especially after some changes in the configuration. I changed some doctype aliases to be better organized after building an additional (german) blog in the same umbraco installation. I double checked the xslts, the masterpages, the rss builder and my action handlers but not the Usercontrols (I have only one actual).

Checking the logs via my ClientTools LogViewer I saw that someone was trying to add a comment and it failed due to the usercontrol code which was using the fault doctype alias. So if you are the one who wanted to add a comment: It's working again.