Reinstall Nebula3 FREE last setup using the same path for everything. Seems to be an error into INIT files that Nebula must load when you load Nebula3 FREE into your sequencer (could be a path error or a corrupted file).
If the same error reappears. You should post in this threat you .XML file from you Acustica folder.
Enrique Silveti. Acustica Audio customer and technical support.