This error might also be an indication that you do not have Microsoft Office installed, and are perhaps planning to use PowerWorship with OpenOffice 4.x.
This is fixed as of PowerWorship 4.0.1, which was released on January 23, 2014.System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.Office.Interop.PowerPoint, Version=126.96.36.199, Culture=neutral, PublicKeyToken=71e9bce111e9429c' or one of its dependencies.
The .NET Programmability Support feature is no longer required for Microsoft Office, and the Microsoft Office interop assemblies do not need to be installed to use PowerWorship with Apache OpenOffice.
To install the fix, please download and reinstall PowerWorship 4.0. There is no need to uninstall the software first. You can install over top of your existing installation, if you prefer. Or you can optionally uninstall / reinstall.