qgis - How to achieve better Dissolve results?

I applied the Vector>Geoverarbeitungswerkzeuge>Auflösen (Dissolve) on a zoning plan (see picture zoning plan). I used the attribute village name as the dissolving criteria. The resulting geometry for the village (yellow colored) is sprinkled with small polygons or also larger polygons are not dissolved (see picture sprinkled geometry). In the attribute table the information is in one row.

Are there any approaches to obviate this? Changing any settings? I am using QGIS 1.7.2-Wroclaw.