r.poly - v.support warnings

I run r.poly to get a vector from a raster map. I can display both with
nop problems. Then when I run v.support to build the topology
information I get a lot of messages of the kind:
WARNING: area 751 label: 1 matched another label: 1.
What are the consequences of these warnings? how could I avoid them?

iThis particular warning has no consequences for you. It means that grass
finds two identical labels for one area, so only one (the last one mentioned)
is kept attached to the area. To avoid these messages, try v.clean and/or
v.digit (Remember where it says "Do you want to compress the atts file?",
answers Yes).

Martijn van Leusen

Thanks
Agus.