buildbot exception in on ofbiz-trunk

[buildbot]

The Buildbot has detected a build exception on builder ofbiz-trunk while building . Full details are available at:
    https://ci.apache.org/builders/ofbiz-trunk/builds/1053

Buildbot URL: https://ci.apache.org/

Buildslave for this Build: silvanus_ubuntu

Build Reason: forced: by IRC user <jleroux> (privmsg): forces manual build trying to use gradlew (trying gradle (no path))
Build Source Stamp: HEAD
Blamelist:

BUILD FAILED: exception shell upload_2

Sincerely,
 -The Buildbot