The unexpected volume of visitors that overwhelmed the federally operated health insurance exchange last week is only one of many problems confronting this entity and the state-based exchanges. For starters, some insurance companies have received faulty enrollment data from the U.S.-run insurance exchange, according to insurance industry consultants interviewed by Bloomberg News. Either the plans have been unable to open files forwarded to them from the exchange or have found that the information on the enrollees is incomplete. According to consultant Bob Laszewski, the plans are trying to fix the errors manually. Another consultant, Dan Schuyler, told Bloomberg that unless these problems are rectified in the next few weeks, some enrollees might not have coverage on Jan. 1, 2014.