unable to install PHP under redhat 7

Hi, I was using Redhat Linux 6.2 / PHP / MySQL / apache / modssl / openssl. Everything running smoothly without any problems. But until , I have brougt Redhat Linux 7 and make a bad decision to upgrade my system to Redhat Linux 7...Now, when I start my apache server with the following command ..../usr/local/apache/bin/apachectl startssl....I got the following error messages stating that there is a problem with my PHP. the error messages is that "Cannot load /usr/local/apache/libexec/libphp4.so into server: libgd.so.1: cannot shared object file: No such file or directory " then, I have tried to recomplie my php, but the same problem is still present. If I remove the "LoadModule php4_module" and "AddModule mod_php4.c" then everything works fine. Also , I have checked that libphp4.so is presented under the dir of /usr/local/apache/linexec. Please tell me how to overcome this problem otherwise I will be fired by my company. Thank you so much for your help. Mark