SWIG-PHP error: Invalid library

[loggy]

I'm new to SWIG and I'm trying to make a PHP5 wrapper around this libraryhttps://sourceforge.net/projects/zinnia/The project includes the interface file zinnia.iFollowing www.swig.org/Doc1.3/Php.htmlI run\[code\]swig -php -c++ zinnia.igcc `php-config --includes` -fpic -c zinnia_wrap.cppgcc -shared -L/usr/local/lib/ -lzinnia -o zinnia.so\[/code\]Then I load it in PHP\[code\]extension=zinnia.so\[/code\]But when I start apache I get this error\[quote\] PHP Warning: PHP Startup: Invalid library (maybe not a PHP library) 'zinnia.so' in Unknown on line 0\[/quote\]Does anyone know how to solve it?Apache/2.2.14 (Ubuntu) PHP/5.3.2 Swig 1.3.2Thanks