When you install an addon like SItoA, you may see an error like this the next time you start Softimage:
// ERROR : 2356 - This plug-in is not installed: ArnoldRenderPreferences
That’s because addons like SItoA install custom preferences, which are left behind when you uninstall the addon. At startup, Softimage finds the custom preference but can’t find the plugin that owns the preference (because it’s been uninstalled).
To get rid of this error, go to your Softimage user folder, and delete the Data\Preferences\Arnold Render.preset file.
In this case, a customer running Maya 2013 on Ubuntu reported this error when he tried to load the mtoa plugin:
API error detected in plugins/mtoa/Main.cpp at line 710: (kFailure): Unexpected Internal Failure
ERROR | Failed to register renderer 'arnold'
That specific line in plugins/mtoa/Main.cpp runs these two lines of Python:
So I asked the customer to run that Python in the Maya script editor, and that gave us this error:
# Error: ImportError: file
/usr/autodesk/maya2013-x64/lib/python26.zip/hashlib.py line 63: No module
named _md5 #
Now we’re cooking with EVIL gas! I’ve seen these kinds of errors before…
This appears to be general problem with Maya 2013 and pymel (I found a few different posts about this via Google search). For example, this thread from the pymel project, or the Troubleshooting section on this page.
In brief: you need to create some symlinks to the right versions of the libssl.