I installed the latest KDE 4.4 on a Windows machine (Vista) and I was surprised that the bug with Okular is still present. It is impossible to open a file, it gets me an error message.

What I wonder is if installation is a matter of misconfiguration, because I installed it over an older installation, or the bug is still unfixed.

During installation runs with this and earlier versions I often got problems during install. I learned to use the Winkde mirror to keep the level of such installation problems lower but you still get these problems. Is this a general problem or do I need a clean install?

Please try upgrading to 4.4.1, it should be fixed in that release.