.NET Framework 4.5 moved some classes, including the class mentioned above, from System.Core to mscorlib. This can cause errors on machines that have .NET Framework 4.0 installed, but __not__ 4.5. One way this can occur is with an incorrect ILMerge. Please take a look at [this SO answer](http://stackoverflow.com/a/13750130/934891) based on a similar issue.
I can update the machine I'm working on, but some users out there may not be able to for whatever reason. It would be good if the toolkit were truly compatible with an out of the box 4.0 system.
I can update the machine I'm working on, but some users out there may not be able to for whatever reason. It would be good if the toolkit were truly compatible with an out of the box 4.0 system.