Problem in Paypal Payment PRO in OsCommerce.

Hi,

Can anybody help me with Paypal Payment PRO in OsCommerce..

I have downloaded the contribution from the oscommerce site
http://www.oscommerce.com/community/contributions,3716

Have installed according to the instructions. But when i run this it

shows a file is missing (pear.php)..

I want to add this paypal pro in this site..

http://www.perceptionsystem.com/osco...dia-smartdevic

es.html any oscommerce master please let me know how to make the Paypal Pro Working on Oscommerce

Thanks a lot
john98
webmaster@perceptionsystem.com