Well, either this is a very uncommon problem, or it's one which is not easily fixable.
Let me ask an additional question to anyone who is using Plesk on a Windows Server 2008 R2 box.
Do you get the same kind of error as I described in my above post when trying to install Dolphin or Elgg from the...
I have a freshly installed 'Microsoft Windows Server 2008 R2 Service Pack 1' VPS with Plesk 11.5.30.
When installing certain applications (for example, Dolphin, Elgg), it halts with the following error message:
Requirements: Apache module - The app requires the 'rewrite' web server module...