Asterisk-A2billing issue

Hello everyone,

I get this error when attempting to make calls on my asterisk system configured with a2billing

Launched AGI Script /var/lib/asterisk/agi-bin/a2billing.php PHP Fatal error: Class 'AGI' not found in /var/lib/asterisk/agi-bin/a2billing.php on line 59

Does anyone know the cause?

a2billing installation error. AGI.php is not part of Asterisk.