Hi mattster42, last week I had a lot of the same error messages you mention. Took me days with install/reinstall but finally had it to work on a config that looks like yours (Win2003, IIS6, PHP5.3.3, MySQL 5.1.49).
The tips I can give you:
Read this page carefully and follow the steps for configuring FastCGI:
http://learn.iis.net/page.aspx/248/configuring-the-fastcgi-extension-for-iis-60/
I had to create the MySQL database manually, the setup program wasn’t able to identify the possible collations. Just create an empty database and process the MODx setup if you run into this too
Read the PHP.INI file and see which settings you really need to change when using IIS
Check the FCGIEXT.INI file in your Windows\System32\inetsrv directory for the correct settings pointing to your php-cgi.exe
It might be that MODx cannot handle a database with a figure in the name. This is not confirmed but for me some problems seemed to be gone when I no longer used a database with a name holding a number in it
I also downloaded php_browscap.ini from
http://browsers.garykeith.com/downloads.asp and added an entry in PHP.INI
Maybe one of the tips will help you and prevent you from loosing as much hairs on this as I did!
Kind regards,
Maurits, The Netherlands