This is an old thread, but maybe it'll help someone. The issue is that in the soap project file there's a reference to a class that doesn't exist. The error message is because it thinks it's a variable not a package name. Probably the exact same issue I had, but could apply to similar misleading error messages.
groovy.lang.MissingPropertyException: No such property: org for class: Script1
Error is caused because the Groovy class "TimeCategory" moved.
org.codehaus.groovy.runtime.TimeCategory in groovy-all-1.8.0.jar which is part of SoapUI-4.5.1
groovy.time.TimeCategory in groovy-all-2.4.4.jar which is part of SoapUI-5.4.0
You just need to fix the reference
use (org.codehaus.groovy.runtime.TimeCategory) -->