[archiver] out of memory

I'm getting this message when trying to restore a 25MB dump. The backup was generated from a postgis database, so it has (smalls, in this case) blobs inside.
Searching in the files, I found a Tom Lane's message suggesting the use of pg_dump -d option in a similar situation because, at that time, there was some issue about the COPY command.
Well, when I use the normal commands <pg_dump -h localhost -U postgres -F t -b -d MAPAS > MAPAS.tar>, the restore operation <pg_restore -d MAPAS MAPAS.tar> shows the message "[archiver] out of memory" almost immediately.
If I use the combination <pg_dump -o -C -b -Ft -i -O -v MAPAS > MAPAS.TAR>, the restore <pg_restore -Ft MAPAS.TAR -d MAPAS> doesn't show the message, but takes hours quietly consuming 99% of my CPU and 30% of my RAM. With no result...
Any tips?

[]s

Jomar