Am having similar problem on SQL2005 sp2 and sp3. Crystal Reports running on server B using SQL account to connect to server C, the reports run okay, but ERRORLOG on C has multiple "Error: 18456, Severity: 14, State: 8"
Have ran " sp_change_users_login 'update_one', 'ReportUser', 'ReportUser' " for databases involved in reports
Server C security event log looks normal.
Only this SQL account and only form server B is having this problem.
This has had me stumped for months.
Am having same problem with multiple sql accounts on another server, but that is for another day.