I have the same problem as many others who use one.com, but every fix i have found was writen for 2.0.7. It dont seem to work with the new 2.1.
The usual line you have to change is this:
status_header($status); // This causes problems on IIS
Before i did that, my installation did not finish. After i applyed "//" in front of the line, the installation worked.
But now i have the "blank page" problem in almost every page. When i press "submit" og "update" in dashbord, it refresehs the page and the page goes blank.
The post are posted and the changes are made, but i have to manually edit the URL to http://www.mysite.com/wp-admin/ to get back in to dashbord.
I have tried the wordpress-2.0.5-tuneup.phps also, but it did not show up under "plugins".