What is this error?

[Dean F.]

ImportError: /usr/local/lib/python2.7/dist-packages/noise/_perlin.so: undefined symbol: grad2

I get it when running worldengine, of course.  :)  I have tried several invocations, and all get the error.  A typical one is:

worldengine -worldname=test -step=full -width=8190 -height=4095 -number-of-plates=20 -verbose -rivers=rivers

Thanks