"Not able to find unused port to start applet's ServerSocket"

We are running ENOVIA V6R2013x with various hotfixes.

One of our Win7 Internet Explorer11 users began to experience the following unfamiliar error after returning to work this past Monday every time he logs onto ENOVIA: "Not able to find unused port to start applet's ServerSocket"

Seemingly no one at our company has encountered this error before and we have tried all our known troubleshooting methods without success. This same error is repeated when the user attempts to connect to ENOVIA from CATIA to upload/download files.

 I tried searching the Dassault Knowledge Base and did not find any matching hits.

Has anyone encountered this pop-up error before, and if so, how did you resolve it?