If communication between your computer and the EggBot is working — as in, you can send a plot and have the machine move in response without generating error messages — then there is no reason to suspect that a change in operating system is a factor.
The most likely cause of an issue with that description is that something is physically loose on the EggBot– perhaps the pen arm, perhaps the egg, perhaps something else. When the EggBot motors are powered on, both the egg and the pen holder should resist motion if you try and move them a little. That might help point the way towards what is causing the problem.
You might also want to have a look through our EggBot Quality Troubleshooting Guide, which shows the effects of different types of mechanical issues: http://wiki.evilmadscientist.com/Eggbot_Quality_Troubleshooting
