Antivirus and anti spyware together?

i am using Avira Antivirus free with ZoneAlarm free firewall. i also install Spyware Terminator free, Malwarebytes free and Threat Fire free. I know you should only install one antivirus program, but can all this protection software coexist together? Will they cause problem to my computer in the future? Plz help with an expert answer.