We have developed an application for our customer that runs as a windows service on windows 7.

We developed it using Visual Studio 2015 (.NET 4.5.2) against Sage 50 Pro Accounting 2016.

The customer is using 2016 Sage 50 (I think the Quantum edition).

The server runs with a plug-in architecture, so the application is compiled as a class library and the server load it into memory and executes it as needed, using code similar to:

Assembly PlugInAssembly = Assembly.LoadFrom(ProcessorPath);

Type processorType = PlugInAssembly.GetTypes().Where(t => !t.IsInterface && !t.IsAbstract && typeof(FileProcessor).IsAssignableFrom(t)).FirstOrDefault();

FileProcessor processorObj = (FileProcessor)Activator.CreateInstance(processorType);

This architecture has worked well for us in the past on other projects, but this is the first time we are trying it with the Sage .NET SDK (sage50sdk_2016_2).

We developed our app and it worked well on our computers. When we installed it on the customers computers, it’s been throwing errors.

This is the stack trace:

Error message: Could not load file or assembly 'Sage.Peachtree.Domain, Version=2016.1.0.114, Culture=neutral, PublicKeyToken=d06c16dde04d83e4' or one of its dependencies. The system cannot find the file specified.

Stack Trace:    at Sage.Peachtree.API.PeachtreeSession.Begin(String applicationIdentifier)

   at gdcQuattroToSage.Processor.VerifySageAccess()

   at gdcQuattroToSage.Processor.Initialize()

I was able to confirm the file exists at: C:\Program Files (x86)\Sage\Peachtree\Sage.Peachtree.Domain.dll

Looking at the Windows Properties of the file, it states that it’s version 2016.0.00.0090 on both the customers computers as well as my own.

Any ideas on how to fix this error?