Why W3 validator is not working properly?

I have very urgent website to be done and as client want it to XHTML validated. As only w3 validator (a href="http://validator.w3.org)" rel="nofollow"http://validator.w3.org)/a can do it.. but when i upload file, it throws server problem or port issues or bad gateway etc. all rest pages are working fine within website except the validator itself.. plz suggest any remedy or is any other option which can provide me Xhtml validation??? plz help?? its urgent!!