java.lang.RuntimeException on W3C CSS Validation Service

Hey, I love your validation service.
but I've been using it for CSS 3, it raises java.lang.RuntimeException.

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http://jigsaw.w3.org/css-validator/validator?uri=http%3A%2F%2Fjuggler.jp%2Fd%2Fstyle.css&profile=none

W3C CSS Validator results for http://juggler.jp/d/style.css (CSS level 3)
Sorry! We found the following errors (1)
URI : http://juggler.jp/d/style.css
-1   Unknown error java.lang.RuntimeException
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To replicate error case, Please find the attached CSS file.

If there is anything I can do to help you for this issue,  let me know.

Thanks,