Problem:
A web application may appear to be able to create an output file from the development machine with the Solo webserver. Once deployed on an IIS server, the output file may not be created.
Resolution:
Make sure the output file is created in a directory where the application has permissions. Since the application in some instances is executed by IIS, which has its own user id to execute the web application or access some allowed resources, make sure it has access to the directory where the appplication will create the file.