Cloth will not simulate when you scrub along the timeline. Delete the cache and then allow the simulation to run, create a playblast to see the results. IF still no joy it could mean that the collision was not created correctly.
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)