If your application uses an application configuration file, e.g. myapp.exe.config, it won't be loaded by default when the fitSharp Slim server runs. To specify the application configuration file, change the COMMAND_PATTERN definition.

!define COMMAND_PATTERN {%m -a c:\mypath\myapp.exe.config
 -r fitSharp.Slim.Service.Runner,c:\program files\fitsharp\fitsharp.dll %p}