fTools-Error: "...invalid geometry..."
I have encountered the same problem elsewhere. Reset the CRS. Go to Settings>Project Properties> CRS and Set a Reference system again. This should do the job. If not, export it as an ESRI shapefile.
I have encountered the same problem elsewhere. Reset the CRS. Go to Settings>Project Properties> CRS and Set a Reference system again. This should do the job. If not, export it as an ESRI shapefile.