Can't find localhost

Newbie question

I have Firebird 1.5 installed on w2k and I can connect to it with isql, IBOconsole, and in Excel via a DNLess connection in VBA-ADO, but when I try to connect in PHP 5 I get a cannot find localhost error.

connect localhost:c:\data\popeyes.fdb USER SYSDBA PASSWORD masterkey;

I tried using IP, leaving localhost off ( that yields cann't open database), ADOdb to no avail. Connection to mySQL and sqlLite works fine.

What am I doing wrong?

TIA, jim_racster

example:

$db = ibase_connect('127.0.0.1:\\IB_DATA_ENV\\xx.gdb', "username", "password", "codePage");

!!!! \\ is important !!!!!