error submitting css file for validation by direct input

 A critical error has occurred. Below is a stack trace from Unicorn, please
copy and submit in a bug report <public-qa-dev@w3.org> to help us solve the
problem.

class java.io.IOException
Error writing to server
sun.net.www.protocol.http.HttpURLConnection.writeRequests(HttpURLConnection.java:578)
sun.net.www.protocol.http.HttpURLConnection.writeRequests(HttpURLConnection.java:590)
sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1193)
org.w3c.unicorn.util.ClientHttpRequest.post(ClientHttpRequest.java:397)
org.w3c.unicorn.request.DirectRequestPOST.doRequest(DirectRequestPOST.java:81)
org.w3c.unicorn.RequestThread.run(RequestThread.java:66)

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Imagination is more important than knowledge.
**For knowledge is limited to all we now know and understand, **while
imagination embraces the entire world, and all there ever will be to know
and understand. *
* - Albert Einstein*