buildbot exception in MacPorts on ports-10.6_i386-watcher

[buildbot at macports.org]

The Buildbot has detected a build exception on builder ports-10.6_i386-watcher while building macports/macports-ports. Full details are available at:
    https://build.macports.org/builders/ports-10.6_i386-watcher/builds/4681

Buildbot URL: https://build.macports.org/

Buildslave for this Build: ports-10.6_i386

Build Reason: The SingleBranchScheduler scheduler named 'ports' triggered this build
Build Source Stamp: [branch master] d13d381938ab888e70024885f834682a35ad868f
Blamelist: David B. Evans <devans at macports.org>

BUILD FAILED: exception

Sincerely,
 -The Buildbot