Why do I occasionally get this error with both new and old disks when ripping? Very frustrating!

Error converting to FLAC, 'Track 1' to '/Users/alferguson/Music/Brubeck Brothers Quartet, The/Intuition/01 Brubeck Brothers - West of One.flac'
Unable to read CD, check CD disc (frame LBA 0 ripping 26 frames track end LBA 34666) [Rip]
Error converting to FLAC, 'Track 2' to '/Users/alferguson/Music/Brubeck Brothers Quartet, The/Intuition/02 Brubeck Brothers - Sahara Moon.flac'
Unable to read CD, check CD disc (frame LBA 34666 ripping 26 frames track end LBA 74271) [Rip]
Error converting to FLAC, 'Track 3' to '/Users/alferguson/Music/Brubeck Brothers Quartet, The/Intuition/03 Brubeck Brothers - Parade Du Funk.flac'
Unable to read CD, check CD disc (frame LBA 74271 ripping 26 frames track end LBA 115374) [Rip]
Error converting to FLAC, 'Track 4' to '/Users/alferguson/Music/Brubeck Brothers Quartet, The/Intuition/04 Brubeck Brothers - Bullwinkle's Revenge.flac'
Unable to read CD, check CD disc (frame LBA 115374 ripping 26 frames track end LBA 154139) [Rip]
Error converting to FLAC, 'Track 5' to '/Users/alferguson/Music/Brubeck Brothers Quartet, The/Intuition/05 Brubeck Brothers - Still as Winter.flac'
Unable to read CD, check CD disc (frame LBA 154139 ripping 26 frames track end LBA 195989) [Rip]
Error converting to FLAC, 'Track 6' to '/Users/alferguson/Music/Brubeck Brothers Quartet, The/Intuition/06 Brubeck Brothers - Open Door.flac'
Unable to read CD, check CD disc (frame LBA 195989 ripping 26 frames track end LBA 236739) [Rip]
Error converting to FLAC, 'Track 7' to '/Users/alferguson/Music/Brubeck Brothers Quartet, The/Intuition/07 Brubeck Brothers - Jump Up, Get Down.flac'
Unable to read CD, check CD disc (frame LBA 236739 ripping 26 frames track end LBA 265474) [Rip]
Error converting to FLAC, 'Track 8' to '/Users/alferguson/Music/Brubeck Brothers Quartet, The/Intuition/08 Brubeck Brothers - Easy for You to Pray.flac'
Unable to read CD, check CD disc (frame LBA 265474 ripping 26 frames track end LBA 296868) [Rip]
Error converting to FLAC, 'Track 9' to '/Users/alferguson/Music/Brubeck Brothers Quartet, The/Intuition/09 Brubeck Brothers - Change Up.flac'
Unable to read CD, check CD disc (frame LBA 296868 ripping 26 frames track end LBA 314456) [Rip]