[Cannot Redeclare _Pear_Call_Destructors()]

I've not looked at this for a while, but I've tried again and I'm still getting the same error message. 

 

Some help would be good. I've running a version of OpenX on a server that I want to shut down but can't do this until I can get revive working.

[Cannot Redeclare _Pear_Call_Destructors()]

I will look at upgrading PHP, would that change the error message I'm getting? From what I can work out, I've got 2 versions of PEAR running. One that comes with revive and the other which is already on the server.

[Cannot Redeclare _Pear_Call_Destructors()]

I'm trying to do a new install but when I visit the url to start the install I receive a blank page. After looking in the error logs I've got the following fatal error:

 

PHP Fatal error:  Cannot redeclare _pear_call_destructors() (previously declared in /var/www/adserver/lib/pear/PEAR.php:771) in /usr/share/pear/PEAR.php on line 800

 

Server is running php 5.2.17

 

Any help would be appreciated.