This should be mentioned now, but crash logs were not updated in the 1.0.5 version of Mine-imator and a TON of questions about it were simply answered with "update to 1.0.5"
A lot of people have been confused about it since it came out, and real solutions to these questions were not getting resolved correctly due to this issue.
Among other errors, it seems copying a selection of keyframes on a character causes a crash. I dunno why that happens but copying selections of other keyframes works fine. It's only character frames.
However this only happens for using hotkeys (ctrl + c) instead of using the copy function.