If the file does not exist on the windows dir. (My Documents) .. the OpenOffice reject to save the new file in windows dir. and the only way to save the file is to put it in the ubuntu (Home) dir.
Does this happen only with OpenOffice.org, or with other applications as well?
Does your user have enough rights for saving files to the mounted "My Documents" partition?
which could not be read from Microsoft Office under Win. Xp
If its an ext2/ext3 partition see http://en.wikipedia.org/wiki/Ext2#External_links
for applications to read the partition.
The second problem is the resolution of the OpenOffice is not good as all the ubuntu other interface or Win. (It looks Faded)
No idea about that, sorry.