You might try using Disk Utility to repair your permissions (one possibility). Otherwise, you may have to reinstall VBE.
Inside the VBE add-on folder are the viewer executable for Mac and Win. These are bundled with the model when you save a VBE file. It sounds like somehow either the viewer itself or the resulting file is either corrupt or has the wrong access permissions.
As a side note while you work this out, while the viewer apps that you create are read-only (they cannot modify the viewpoints/settings and save new copies) - the main VBE application can OPEN those files and read the rendered (if you used global illumination) model for you to re-save it for another platform, or in this case, after permissions repair / reinstall.
Good luck,
Karl