Fantastico: Fatal Error: Call To Undefined Function Get_output() In

I'm getting the following error when I'm trying to access Fantastico from cPanel:

Fatal error: Call to undefined function Get_Output() in /tmp/cpanel_phpengine.1279687422.23265aCk1JGb5bl on line 319
I have safe_mode set to On and shell_exec function disabled. When allowing shell_exec and safe_mode Fantastico is working in this server.

But I could see that many server's where safe_mode set to On and shell_exec function is disabled and Fantastico is running just fine.