Tomcat 7.0.43 "INFO: Error parsing HTTP request header"

For me, the problem was passing in a larger than normally expected HTTP header. I resolved it by setting maxHttpHeaderSize="1048576" attribute on the Connector node in server.xml.

If you have this listener:

    <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on"/>

on your server.xml, remove it and try. You can not use a keystore if you are using the APR connector