From ASCII to UTF-8

As part of a migration from 8.0 to 8.1 i want to convert the data from
ASCII to UTF-8.

I dumped the database with pg_dump (8.0) and tried to convert it with
iconv, but it shows an error:

$ iconv -t ASCII -t UTF-8 fahstats_data.dump -o fahstats_data_utf-8.dump
iconv: illegal input sequence at position 71407864

That position contains the decimal value 233:

$ od -A d -j 71407864 -N 1 -t u1 fahstats_data.dump
71407864 233
71407865

I could use pg_dump -E in 8.1 but it is in another machine with ADSL
connection and the dump size is 1.8GB. It would take more than 12
hours.

How to install pg_dump 8.1 only? I tried to copy the executable and
the libs but it did not work.

Regards, Clodoaldo Pinto