thank you very much for your bug report.
When UMotion detects the unhandled exception, please click on the "Send Bug Report" button. Bugs like this are often very specific to your project so please provide a small *.zipped example Unity project where this bug can be reproduced by you (if the *.zip exceeds max file size, send the bug report without it, I'm going to send you a link to my Dropbox instead). Also please provide a short step-by-step instruction how I can reproduce the problem with the delivered project.
That allows me to identify an issue very fast and effectively and fix it in an upcoming patch release.
Thank you very much.