I just realized you never told us what version of PHP you're running.
trans-sid support is compiled in by default in version 4.2 and newer.  If
you're running 4.1.x or older, you'll need to recompile PHP or install a
newer version.


Create and view a simple phpinfo() script in your browser:

<?php phpinfo(); ?>

The top table in that page should show you the current configure command.

Copy that and add --enable-trans-sid to it.

./configure <your config string>
make
su
make install

http://www.php.net/installation