That's Microsoft Office - when a document is opened, Office opens a temporary file, which on a NTFS volume would be hidden from the users, however, due to differences in the way file attributes are handled by linux's ext2 file system, they are not hidden on an ext2 volume.
Please note - the files are also created on a Windows file system, they are just not visible.
The temporary files can simply be ignored - they will be deleted when the user closes the document.