Whenever I try to backup my SQL databases, I get the following errors:

2000-05-08 13:16:57.46 spid7 Using 'xpstar.dll' version '1998.11.13' to execute extended stored procedure 'sp_MSgetversion'.
2000-05-08 13:25:11.30 kernel BackupVirtualDeviceSet::Initialize: Open failure on backup device 'DBASQL70TID266VD0'. Operating system error -2147024891(Access is denied.).
2000-05-08 13:32:09.55 kernel BackupDiskFile::CreateMedia: Backup device 'f:\program files\mssql7\data\BACKUP\' failed to create. Operating system error = 3(The system cannot find the path specified.).
2000-05-08 13:32:32.86 kernel BackupDiskFile::CreateMedia: Backup device 'f:\temp' failed to create. Operating system error = 5(Access is denied.).
2000-05-08 13:32:44.47 kernel BackupVirtualDeviceSet::Initialize: Open failure on backup device 'DBASQL70TID656VD0'. Operating system error -2147024891(Access is denied.).
2000-05-08 13:33:46.60 kernel BackupDiskFile::CreateMedia: Backup device 'f:\program files\mssql7\data\BACKUP\' failed to create. Operating system error = 3(The system cannot find the path specified.).

Does anyone know how to fix this?