Here's why: link
After the success of Barbie in the Nutcracker in 2001, and Barbie of Swan Lake in 2003, Mattel Entertainment was supposed to adapt Tchaikovsky's The Sleeping Beauty ballet (the third of the three ballets he created) into a Barbie film, titled Barbie as the Sleeping Beauty. However, the Walt Disney Company filed a trademark application on March 13, 2007, for the name "Princess Aurora" that would cover all live-action and recorded movie, television, radio, stage, computer, Internet, news, and photographic entertainment uses, except literature works of fiction and nonfiction. This has caused controversy because "Princess Aurora" is also the name of the lead character in Tchaikovsky's ballet version of the story, from which Disney acquired some of the music for its 1959 animated film version. Therefore, a campaign has emerged to complain to the U.S. Patent and Trademark Office if people feel this trademarking of a pre-existing character name should not be allowed. The trademark was granted despite this on January 17, 2012.
The move could also sink any movie about the ballet or that uses a scene of the ballet in another movie. This has caused Mattel to abandon Barbie as the Sleeping Beauty film production, and everything was shelved. It would have been the sixteenth Barbie feature film, and the third to be based on a Grimm's fairytale. It was originally scheduled to be released during the fall of 2008, but was pushed back to 2009. Later, it was announced that Barbie and the Three Musketeers would be released in Fall 2009 instead, with no new release date or extra information announced for Barbie as the Sleeping Beauty. Mattel is currently quiet about this to avoid the trademark controversy.
Note: Found it somewhere. I do not own anything.