Change the -1 to 0. It looks like it might be only running from -1 to 0 and stopping.
Also check the playbalsty settings themselves
Chris (formerly R@nSiD)
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When the power of love overcomes the love of power the world will truely know peace - Jimmy Hendrix
Winner SM VFX Challenge 1
3rd Place SM SteamPunk Challenge (May 2007)