server configuration

I have 4 servers with redhat enterprise 3.0 and plesk control panel 7.0 These are my servers in my officed not leased. Redhat and Plesk control panel are installed and operating servers are accessable thru ssh. have problems with program configuration IE internal sever error, mail program is not working and when a new subdomain is put in I get an apache test page instead a Plesk page holder. The problems are the same on all server fix one fix all