If you're being asked for SVN credentials, you're using an old version of the
plugin. Delete everything from application.properties except the line
grails.project.work.dir = 'target'
to BuildConfig.groovy and remove the properties "grails.project.class.dir",
"grails.project.test.class.dir", and "grails.project.test.reports.dir" and
it will reinstall the correct version and you should be able to release.