Joomla! Discussion Forums

Hello
I found something strange with this 'package"
IIS 7.5
Mysql 5.0.5
PHP 5.3.0 VC9 (special for IIS)

When I try to open http://localhost/joomla/ (or any subfolders in /joomla/) I have blank page, no text, no info. Page's doesnt loading, and Firefox says nothing.
IE says Internal Error 500; nothing more.
I trying fix it with no results.

But working for 2 days and I found, that 'standard' version of PHP (5.3.0 VC6) working fine with joomla :| Everything is ok, installer and other pages works without problems.
Could somebody tell me, why this happen?

My other pages on local machine (no matter VC6 or VC9), f.e. flash gallery (mysql), phpBB works fine. Maybe somebody could answer this...

PS I use my local mashine only for testing and when everything is ok, i upload it on dedicated server.

[MOD note: moved to "Joomla! on IIS webserver"]