A phpinfo.php file is a file that makes it easier for us to see information about your server. While it doesn't include version information about MySQL, it does include version information about PHP, Apache/IIS, GD, and other things. It also contains a description of many important settings, which could possibly be causing problems with your installation.
Making a phpinfo.php is simple. Just open Notepad or any other text editor, and enter the following:
<?php phpinfo(); ?>
Now save it as "phpinfo.php". On Windows systems, you should keep the quotes in there when you save it, because this will prevent Notepad from saving it as "phpinfo.php.txt" automatically.
Once you have this file saved, upload it via FTP to your site. You should now be able to access it, and give us its link to help us help you ;).
This topic exists to catch searches and provide a way to easily link to a description of phpinfo.php ;). Just add [[topic:What is phpinfo.php?]] somewhere in your post, and it will be made a link like magic.