I've not used the installer from eZ but the only things that could cause this problem would be ipchains/iptables issues or eZ grabbing the port 10000
Try stopping httpd server as webmin doesn't need it. You should be able to get to webmin then. Otherwise try installing a new rpm for webmin from www.webmin.com
Tony Wood : twitter.com/tonywood
Vision with Technology
Experts in eZ Publish consulting & development