We’ve just had a report of this from another user, and I apologize that we have not had a chance to update the installer file yet.  

We believe that the issue is due to changes made from version 0.48.2 to version 0.48.4 of Inkscape, so you can probably avoid the error by reverting to that version. 

Alternately, download and (manually) install this updated version of our extension: https://code.google.com/p/eggbotcode/downloads/detail?name=eggbot_2013_08_11_2.3.4.zip To manually install the extensions, copy the contents of the ZIP archive to (Program files)Inkscapeshareextensions