I turned on the WinBoot plugin and put setupldr.bin and other required files in the right folders. However, when I start project with the big blue button or if I start plugin with the small green button, I get the error message mentioned in the subject.
When I replaced all %pFileBox2V% with %pFileBox2% and %pFileBox3V% with %pFileBox3% in the [CheckFiles] section, everything went fine.