What is vjslib.dll?

vjslib.dll refers to the Microsoft Visual J# Redistributable Library
The KDCalc Engine for .NET requires the Visual J# Library. You will need the version of vjslib.dll that matches your installed version of the .NET framework. If you are using .NET version 1.0, you will need the 1.0 version of the Visual JSharp Redistributable. If you have .NET 1.1, you will need the 1.1 version of the JSharp Redistributable.

Download the the JSharp Redistributable from Microsoft here.

To find out what version(s) of the .NET framework is installed on your machine, look for the "System" assembly in your global assembly cache. Your Gloabal Assembly Cache is located either in "c:\winnt\assembly" or "c:\windows\assembly". If the the "System" assembly is marked as v1.0.33, then you have .NET v1.0. If the it is marked as v1.0.5, then you have .NET v1.1.