This error appears like this:
To solve this:
First, confirm that IIS is running. If it is, this error is likely because in IIS, the project folder is not converted to application. You can set this by doing the following:
1. Click Start
2. Begin typing "IIS" and select "Internet Information Services Manager"
3. Click on Sites and find Spark by AnaJet
4. Right click on the Spark by AnaJet folder
5. Click Convert to Application
(Image from GPS, but the same folder and settings will exist for Spark for AnaJet if installed)