Taking a screenshot of any issues will help the BigMarker team support diagnose or recreate the problem. If possible, please include a screenshot of your issue in your email.
To take a screenshot on your Mac (iOS): http://support.apple.com/en-us/HT201361
To take a screenshot on your PC (Windows): http://www.wikihow.com/Take-a-Screenshot-in-Microsoft-Windows
Even better, if you can record any issue using QuickTime or another recording application, that can help us as well.