With a key deadline approaching, state officials across the country are scrambling to get the Affordable Care Act's complex computer systems up and running, reviewing contingency plans and, in some places, preparing for delays. Oct. 1 is the scheduled launch date for the health-care law's insurance marketplaces — online sites where uninsured people will be able to shop for coverage, sometimes using a government subsidy to purchase a plan. An estimated 7 million people are expected to use these portals to purchase health coverage in 2014. The task is unprecedented in its complexity, requiring state and federal data systems to transmit reams of information between one another.