H4 approval after H1B approved

[sudiptos]

I am a H1B worker in USA. I changed my company and my H1 approved on 8th June 2007 along with my wife's H4. Now my wife's H1B got approved on 18th May 2007. So the situation is her H4 got approved after her H1. Please let me know
what do we need to do?
will there be any problem when she starts her job from Oct 2007?
Her employer said that its not a problem as her H1B valid from 1st Oct. Please advise us.