[Rcpp-devel] Error in RCpp and Wt toolkit

The example:
http://dirk.eddelbuettel.com/blog/2011/11/30/#rinside_and_wt

From the code:

https://github.com/JohnRobson/Wt-Tests/blob/master/RInside/wtdensity.cpp

After running, the site appears OK: http://imagebin.org/252132

But immediately a segmentation error is throw:
http://paste.ubuntu.com/5659723/

Line 171 Cause this error.

171  R_.parseEvalQ(cmd); // evaluate command -- generates new density plot

What I need to do to fix this error?

Thank you,

John Robson