From your netstat output you seem to have a http process listening on 8080 which may well be your ispconfig:
tcp 0 0 *:webcache *:* LISTEN 5227/httpd
Did you enable SSL? Do you get any difference if you use http or https to access?
Have a poke in logs - maybe a "tail -f /var/log/httpd/error.log" in your console at same time as trying to access the page.
Not important but last available doc issued was for centos 6.4 and is here install doc
. Don't know if there might be any differences between the two.