Deploying an extension

I have manually built version 5.4.8 to /usr/local prefix on debian squeeze. I need to deploy a custom extension mapi.so already precompiled. It is part of deployment .deb package. This package deploys to /usr prefix. From my php.ini, I specify extension="mapi.so deployment path". I didn't try it personally but, others tell me that it works if they deploy php from apt-get. I get this error... PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib/php5/20090626+lfs/mapi.so' - /usr/lib/php5/20090626+lfs/mapi.so: undefined symbol: compiler_globals in Unknown on line 0 Thanks in advance