Comment 14 for bug 278423

Well there are two problems here. The first is that the following text needs to be added where Python modules are declared to allow for the internationalisation thing to work. I am away from home for a few months, so if someone can just insert this it will be great as I don't have my computer to do it with.

import gettext
_ = gettext.gettext

The extension was trying to give an error message - it would seem that the .obj file you're trying to feed to the extension doesn't contain edge data. You need to select the model as "face-specified", as opposed to "edge-specified".

Perhaps to reduce confusion, change line 335 to

inkex.errormsg(_('No edge data found in specified file\n'))
inkex.errormsg(_('Try selecting "Face Specified" in the Model File tab\n'))

and line 329 to

inkex.errormsg(_('No face data found in specified file\n'))
inkex.errormsg(_('Try selecting "Edge Specified" in the Model File tab\n'))

I'm not quite sure what you created the rectangle for. The extension will generate everything itself - it doesn't need a rectangle to act on.