Hilton reportedly admitted during her deposition that she made up the story, but denied any part in it getting out to the media.
Graff's attorney said if a settlement is not reached by May 15, the case will go to trial. The court date was scheduled for Sept. 18.
There was no comment from Hilton or her legal team, E! said.
DISCUSS AND COMMENT ON THIS STORY Reality TV World now offers Facebook Comments on our stories. To post a comment, log into Facebook and then 'Add' your comment. To report spam or abuse, click the 'X' in the upper right corner of the comment box.