Unable to use mcrypt extension but php5-mcrypt is installed

[Przemek Peron]

I have php5-mcrypt installed:
# dpkg -l | grep php5-mcrypt
ii php5-mcrypt 5.4.6-0ubuntu3 amd64 MCrypt module for php5

But php script reports:
Script requires the Mcrypt PHP extension php5-mcrypt

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: php5-mcrypt 5.4.6-0ubuntu3
ProcVersionSignature: Ubuntu 3.11.0-13.20-generic 3.11.6
Uname: Linux 3.11.0-13-generic x86_64
NonfreeKernelModules: fglrx
ApportVersion: 2.12.5-0ubuntu2.1
Architecture: amd64
Date: Thu Nov 21 14:41:01 2013
Dependencies:
 gcc-4.8-base 4.8.1-10ubuntu8
 libc6 2.17-93ubuntu4
 libgcc1 1:4.8.1-10ubuntu8
 libmcrypt4 2.5.8-3.1
 multiarch-support 2.17-93ubuntu4
InstallationDate: Installed on 2013-04-05 (230 days ago)
InstallationMedia: Linux Mint 14 "Nadia" - Release amd64 (20121120)
MarkForUpload: True
SourcePackage: php-mcrypt
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.