Is there a way to connect PHP5 to a Frontbase database?
There seems to be an included connector, but it looks like that is not available anymore in PHP5:
What OS are you using? What kind of PHP package are you using, i.e. if you are on *nix, are you perhaps using a prebuilt version of PHP?
If you can build your own version of PHP, you could perform the steps outlined here: http://www.php.net/manual/en/fbsql.installation.php (i.e. you need to build PHP with the --with-fbsql parameter)
If you're on Windows, you can find prebuilt binaries for Frontbase from the frontbase.com website itself, but they seem pretty outdated (the latest one is for PHP 4): http://www.frontbase.com/cgi-bin/WebObjects/FBWebSite.woa/wa/mainFrame?currentMenu=downloadMenu¤tPage=Download¤tModule=Download&action=downloadArea