In Linux(Centos 6 or higher) ports from 0 to 1024 are reserved for system use. you can force the system to bind to address any port lower than 1024 if you use root or privileged user.
I installed Apache-2.4 from source with non-root user and I solved this problem by allowing port higher than 1024(ex:8080) and modified http.conf file. chang Listen 80 to Listen 8080