Help!problem with change .mb to .egg using Panda Tool GUI

I can not save a .mb to .egg using Panda ToolGUI
It shows in the Panda3DToolsGUI.exe as the below

File “”, line 1455, in SimpleExport
File “”, line 1500, in RunExport
KeyError: ‘quotes’

I’m not familiar with this tool. What is it, and where did it come from?