1804: Unable to save a comment.

praneet*******@gmai***** (Google Code) (Is this you? Claim this profile.)
Sept. 9, 2010
What version are you running?

What's the URL of the page containing the problem?

What steps will reproduce the problem?
1.post-review from svn repository (did not publish)
2.tried to added a comment.

What is the expected output? What do you see instead?
On clicking "save", comment is expected to be saved. but i see an error 
saying a server error "occurred". 
I see following info on clicking "show details"
Error Code: 404
Error Text: Not Found
Request URL: /reviews/api/json/reviewrequests/2/diff/1/file/2/line/40/comments/
Request Data: action=set&num_lines=1&text=ad

What operating system are you using? What browser?
Linux praneeth-laptop 2.6.32-24-generic #42-Ubuntu SMP Fri Aug 20 14:24:04 UTC 2010 i686 GNU/Linux
firefox 3.6.8

Please provide any additional information below.
#1 chipx86
This is basically a symptom of bug 831.