After promising last year to search its computers for tens of thousands of e-mails sent by White House officials, the Republican National Committee has informed a House committee that it no longer plans to retrieve the communications by restoring computer backup tapes, the panel's chairman said yesterday. Karl Rove, for example, sent or received 140,000 e-mails on RNC servers from 2002 to 2007, and more than half involved official ".gov" accounts, the panel has said.