A common error encountered when installing scripts, particulary in Fantastico, results in the following error described in the CPanel Error Log of your account:
"Premature end of script headers" usually means there is a problem with the way the script was coded, or encoded, or
insecure CHMOD permissions
In the latter case, something which is a server-related issue, usually involves incorrect CHMOD settings of '777', when the maximum chmod permission value allowed is 755 for folders, and 400, 644 or 755 for files or 600, 666 if they require write access (recommended values in bold). By changing the CHMOD setting on your file(s) described on the CPanel Error Log would fix the problems encountered. One can change CHMOD settings using a standard FTP client (such as FileZilla, SmartFTP, CuteFTP, WS_FTP, etc.) or via jailed shell access if enabled on your account.
The below website contains more information about the CHMOD settings allowed on our server, that has PHPSuExec, the security feature we have turned on, that prevents insecure CHMOD permissions.
The other common cause of malfunctioning scripts from Fantastico or third-party, are .htaccess files which contain the following error:
The php_flag text in htaccess files are not compatible with the server configuration. To fix, either completely delete the lines starting with php_value, OR add a "#" in front of the text "php_value" each time you see it. This will disable the incorrect code and thus should make your scripts function properly.