The application has failed to start because its side-by-side configuration is incorrect

We've just had this exact same error but the cause was so misleading compared to the error it's hopefully worth adding here as it comes top on google...

The "The application has failed to start because its side-by-side configuration is incorrect" error was occurring when starting a windows service. In our instance this was caused by the services application.config xml file not being valid - someone had edited it manually and pasted in an extra closing tag. Amending this resolved the "not related in any way whatsoever" error message.

The quickest way to check this would be to paste the xml file into one of the many on-line xml validators free on the web.

Dependent Assembly Microsoft.VC90.DebugCRT,... could not be found

Yes, that can only be found on a machine that has Visual Studio installed. The DebugCRT is not distributable. And it doesn't make sense to write C or C++ code and deploy the debug build for it, it is a lot slower.

Deploy the Release build version of your DLL. And the VC++ Libraries, one of the check boxes in the Prerequisites of a Setup project.

This is marked C#, so I'll give the C# answer: Something has mangled your projectname.exe.config file.

Pull it up in a text editor and chances are something won't be closed properly or there will be a few garbage characters at the end. You can figure out why that happened later. But for now, just fix it and you'll be able to launch.