Your comments

Unfortunately i can't simply port it over to the max, as the application relies on WPF which is not available for the Max. Additionally i don't own a Mac.

Right now it is unlikely that i will create a Mac version. Same is true for a linux version.
I'm glad you like Wieldy.
I'm sorry for the problems.

First thing you should verify is, that you have installed the .NET-Framework 3.5 SP1. Please ensure that the SP1 is installed.

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If you're unsure how to check this, you can download the .NET Framework Setup Verification Tool. The tool can be found at:
http://blogs.msdn.com/b/astebner/archive/2008/10/13/8999004.aspx

Just run the executable and verify that the .NET Framework 3.5 SP1 is working.

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Alternatively you can do the following:
1. Open the internet explorer
2. Enter the following string into your address bar: javascript:alert(navigator.userAgent)
3. A popup will show up. In this window search for the string: .NET CLR 3.5.30729
Interesting idea. I will think about it.
Yes. Just double click the header (e.g. Items or Tools) of the ribbon bar, works the same like Outlook 2007/2010.
This has been implemented in beta V0.2.6.656. You can enable this inside the print window (To rightmost button in the toolbar)
Implemented with beta V0.2.6.654
You can now change the tray icon.