Floppy Drive inconsistent between machines.

I have three Pentium 4 desktops which have been loaded with 10:10. Of the three, only one will allow me to read an MSDOS written floppy holding text files using the Desktop/Places/Floppy approach. If I resort to 'mtools' all three machines will read and write to the floppy.

What puzzles me is that two of the computers were converted to LINUX using the same cd which held a download of Ubuntu 10:10. The hard discs were formatted before loading. One of this pair
works normally. The third box was a 10:04 release which had been updated to 10:10.

Whereas 'mtools' gets me out of a hole, it is not an elegant solution. Can anyone suggest where the problem may lie ?

Merry Xmas