I had a similar issue with an Arduino Leonardo board. These steps might help you.
1. Delete all of the eggbot files on my computer.
2. Uninstall the 64bit version of InkScape.
3. I installed the 32 bit version of Inkscape version 0.91 (not the latest version).
4. Then I installed the EggBot Software: version 2.4.0.
5. Once that was installed I changed the eggbot.py file as indicated here: http://forums.jjrobots.com/showthread.php?tid=1199.
6.I then went into the device manager and changed the serial port to com 2 from com 17 for the Arduino Leonardo.
7. At this point I rebooted the computer. After the reboot Inkscape recognized the Arduino Leonardo hardware and works.
I am running Windows 10 on an Intel I7 64bit with 32gb ram and an 8gb video card. The Arduino Leonardo hardware does not seem like the 64bit version of Inkskape and the eggbot.py python file needs to be replaced. Also make sure your serial port is 4 or below on the com ports.
I have 2 other Eggbots using the Eggbot boards and they work fine with the latest version of Inkscape. However, I like some of the extensions in the 0.91 version of Inkscape that were deleted in the newest version of Inkscape.