At any rate, the first part of the error is what happens when the .NET runtime is unable to load an assembly that was requested, which would usually be in a .DLL file. Normally, for a deployed application, this DLL would be in the same folder as the executable file. Check your ChasePlane folder, where the .exe is, and see - is slimdx.dll there? If it is, then it might be a versioning issue; when you load an assembly in .NET, you can specify a specific version to load and if this version is not found, even if another version of the DLL is there, you'll get this error. But you would usually get the version information supplied in the error message, and you'd need that to check.