I'm having this exact problem, versions of software I'm running below.
4images 1.7.1
Apache/2.0.53 (Win32)
PHP/5.0.4
MySQL 4.1
This occurs right after I click "Start Installation" button on the 4images installer.
Fatal error: Call to undefined function mysql_connect() in C:\Program Files\Apache Group\Apache2\htdocs\includes\db_mysql.php on line 39