Grails 1.3.1 dependency resolution

After upgrading Grails to 1.3.1 from 1.2.2, I repeatedly received "UNRESOLVED DEPENDENCIES" errors. After an inordinate amount of troubleshooting, I stumbled upon the sole archived message on the Internet that recommended deleting (or renaming) the %USER_HOME%\.ivy2 directory. Sure enough, this worked like a charm, so I post the resolution here for posterity. It seems there were some transitive dependencies that weren't getting sorted out. It's all good now.