PHP Fatal error: Call to undefined function posix_getpwuid()

I found that this error appears rather often online but almost no one has any idea why it would come up.  I found this error myself today while doing an install of FreePBX on Fedora 14.  My full error was: Checking user..PHP Fatal error:  Call to undefined function posix_getpwuid() in /usr/src/freepbx-2.8.1/install_amp on line 728 This …