WebRick Page not found on strange URL's

I noticed today that the WebRick server displays a page not found for a
file named use_case_analysis,{28014615-A62F-452D-B821-30C7CAB0EC44}.html

Is this bad URI syntax? I am not happy with the strange characters in
the filename but unfortunately this is not my doing and I cannot change

Probably this means I cannot use the WebRick server?
Anyone experienced this before?

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