Installing and upgrading help

I downloaded the stable version of Moodle 1.4 and unzipped to the server directory (running with PHP 4.3.4/MySQL/Apache 1.3/Debian Linux 2.4.2). Now I start to go through the installation through the browser and fill up the details of the database. I have followed the instructions on Moodle.org/doc and created the db, user and password as instructed. When I click on Next, I get a blank page, rather quickly. Why is this?

Incidentally, I also increased the PHP memory limit to 16M, filled up config.php with the same information as on the db page within the install process. Now the very first page shows up blank.

Any help would be greatly appreciated!

Thanks -
Shankar