Post-grunge rockers the Foo Fighters will not play Woodstock '99 next month for unspecified reasons, according to a publicist for the event. The band joins Aerosmith and Jeff Beck as artists who have dropped off the festival lineup over the past month. Aerosmith's management cited production issues, while Beck ran into a scheduling conflict. The Foo Fighters, fronted by ex-Nirvana drummer Dave Grohl, are in the midst of recording a new album, the follow-up to 1997's The Colour and the Shape. The omissions leave the current Woodstock lineup at 38 artists. The festival takes place July 23-25 at Griffiss Technology Park in Rome, N.Y.