Page fault error

Recently several programs have been producing page fault errors in rpcrt4.dll and then shut down. MS indicates that the corrected version should have a date of 11/20/2000, but the one I have is dated 4/99. Where do I get an updated version? I can’t find a download at MS. Some program must have installed an old version, because I have used some of the programs for years with no problems. Sometimes it even causes a page fault when trying to print an email. HELP