I recently got the same error as Scott but doing './gradlew cleanbuild deployApp' did not resolve the issue. A response to a similar issue on stackoverflow (https://stackoverflow.com/questions/33546759/gradle-occurred-starting-process-command-npm-on-mac/) indicated that './gradlew --stop' has resolved a similar issue. I'm not sure why stopping the gradle daemon allowed './gradlew cleanbuild deployApp' to successfully complete, but it worked for me so I thought I'd pass it on.

-Will