One of my workflows involves outputting DBFs from a MySQL database to join them with shapefiles in QGIS. I often clean them up in OpenOffice Calc before making the join in QGIS.

Often I’ll get a general input/output error when I try to open a DBF in Calc.

Solution: Install OpenOffice Base. It’s not automagically installed with the rest of the OpenOffice suite with Ubuntu, so it’s easy to overlook after a clean install. You need to do this to work with DBFs in QGIS, too. Your join will fail, otherwise.