Hi Gil,
Sorry for the late reply, It is not recommended to use multiple antivirus program on the computer. It may cause system stability. For more information refer this link:
Should I use more than one antivirus program?
http://blogs.msdn.com/b/securitytipstalk/archive/2013/01/22/should-i-use-more-than-one-antivirus-program.aspx
I would suggest you to temporarily disable antivirus program and firewall and check.
Warning: Antivirus software can help protect your computer against viruses and other security threats. In most cases, you shouldn't disable your antivirus software. If you have to temporarily disable it to install other software, you should
re-enable it as soon as you're done. If you're connected to the Internet or a network while your antivirus software is disabled, your computer is vulnerable to attacks.
Hope this helps.