Equation Editor Installation instructions on Phpbb3

Problem sloved! In "posting_body.html"

Find:

<textarea name="message" rows="15" cols="76" tabindex="3" onselect="storeCaret(this);" onclick="storeCaret(this);" onkeyup="storeCaret(this);" onfocus="initInsertions();" style="width: 98%;">{MESSAGE}</textarea>

Replace with:

<textarea id="message" name="message" rows="15" cols="76" tabindex="3" onselect="storeCaret(this);"
onclick="storeCaret(this);" onkeyup="storeCaret(this);" style="width: 98%;">{MESSAGE}</textarea>