Ubuntu :: Check Harddisk And File Integrity?

I want to get a program to check (a) hard disk and (b) file integrity. I have had a file - ODS spreadsheet accessed using LibreOffice - that appears corrupt. I have drilled down and down and eventually identified a corrupt component image inserted in a sheet.

The error that is thrown by LO is a "Error saving
the document FILE: Write Error. The file could not be written."
error. The thread can be read here... http://thread.gmane.org/gmane.comp.d...fice.user/9266.

What has confused me is that my machine can not save the file once a sheet is deleted. It is specific to a particular file. The file is stored on n ext4 disk mounted by fstab. I also share the file using samba. Regardless of how I access this file I get the error. If however, I access the exact same file using OpenOffice 3.1.0 OOO310m11 (Build: 9399) from an old Windows Vista Tablet and I can manipulate the file successfully - no error is encountered. I can also access the same file from another Ubuntu machine via NFS and Samba and both work. I am confused. I am beginning to think my disk is damaged or something. How do you check hard disks to verify that the disk surface is intact, and that the expected file sum value matches the value stored in the Linux equivalent to the FAT table.

I am using Ubuntu 10.04 LTS and all hard disks are formated with ext4. All formatting and management of the disks have been done using the 'Disk Utility' in the System > Administration' menu. If I look in gparted it will not check the disk the file is on stating "eslabel: no such file or directory... couldn't find valid filesystem superblock...". The filesystem mounts OK however without any errors. Another harddisk on the same system currently being used for backup does not even have the menu option for checking the disk highlighted.

What is the best way of verifying the integrity of the filesystem, actual files and the underlying physical media? I should point out it is only this single file that currently displays any issues. I either have a damaged disk, corrupt file or LibreOffice has a very peculiar bug that only appears in a unique combination of events just on my machine. As part of my investigations I have been updating ubuntu, reinstalled LibreOffice from their website and checked all dependencies have been met.