Your second hard disk has errors. Becoz you added the fstab entry, fsck automatically checks that drive. fsck runs with -a flag (automatically repair) and it is not being able to do so.
When dropped to the shell, you can run fsck on the drive manually. Ask for interactive repair of file system.
Remember to be careful with FS repair. Is the hard disk spoilt (bad sectors etc) or just had a hard reboot? fsck sd be able to repair the FS if there is no major problem.
Remember to read "man fsck".
Better to remove the fstab entry for the hard disk. Run fsck on hdb after booting into your system. Dont run fsck on the mounted partition
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Bhaskar.