The meshtool has not been uploaded recently. Previous versions of Vortex relied on an XML format for mesh loading, but it had several issues with large files (the XML parser I am using crashes). That's why I created the new binary format which loads much faster and is robust. The problem is that the UI based meshtool relies on an external app (the meshtool.exe program inside the data folder) to convert the meshes. That is a command line tool written in C++ that uses Irrlicht to read the mesh, and then generates the XML. Then the UI meshtool (written in Monkey) parses the XML and creates the binary format.
Of course, the XML step will be removed entirely in the final version, so the command line app will directly create the binary mesh, that you can view and tweak on the UI tool. That will fix the problem. Changing that is not in my current plans for beta2, but I could give it a higher priority, as long as I am capable of doing it in the 2-3 week deadline that I have for the beta2 release.