[Qgis-user] simplify feature

[Jan]

Hi,

I am new to QGis and I have tried to use the simplify feature. I have a 
very large shape file with country and other administrative borders 
world wide. I would like to reduce the file size (complexity).
I have tried different tolerances like 500 or 1000 but I do not see any 
effect in the file produced.
Any ideas?

I have used the windows gis installer with grass included.

Jan