kevin
you need to configure and compile php with the --with-sybase-ct=/opt/sybase option as well as your standard options. (assuming your sybase is in /opt/sybase)
make sure you do a $make clean to uninstall previous php binaries
the way to check if your sybase module was successfully compiled in is to view the phpinfo()
under "Configure Command" the value should be
"./configure' '--with-mysql' '--with-sybase-ct=/opt/sybase' '--with-apache=/usr/tmp/apache_1.3.14' '--enable-track-vars'"
if u scroll down phpinfo, there should be table heading "sybase_ct" this will verify if ur sybase was successfully installed.