Question : Jython

Hello,
I made a quick search on the following error, yet nothing came up on the internet.  Might you know what it means?
 "Invalid external source folder specified: C:\jython\jyton.jar"

It was running fine, then this appeared in the Eclipse explorer.

Answer : Jython

Is this steaming directly through the web? Try to reset Explorer in Tools - internet options - advanced - reset.