Miss Ghana pushed Veruska Ramirez and to newly elected Miss Universe Wendy Fitzwilliam while trying to congratulate her. It's a good thing she was held in the shoulder by the new Miss Universe that prevented her from falling and more embarassment.
The fall almost happened also to Miss France Emmanuelle Chossat in 2003 in Panama. This occurred during the dress rehearsal that was opened to the audience hours before the final contest of the Miss Universe.
And if you think this started only during the late nineties, then you're wrong. In 1965 Miss Universe in Miami, Florida, Miss Colombia Margarita María Victoria Ocampo Gómez fell down gracefully from the stairs and nonetheless she was Top 15.