Single-table backup failure

I often perform single-table backups using pgadmin.
Recently, a problem occurred while doing that kind of backup using pgadmin
1.6.2 and PostgreSQL 8.2.1 on a Windows XP server:
When trying to backup a table contained in a specific schema, pg_dump can't
find the table.

For instance, I have a database named 'mdg', containing a schema named
'art', in turn containing a table named 'tefh'.
When I try to backup this table to the root directory with pgadmin, it
generates and executes the following command:

pg_dump.exe -i -h localhost -p 5432 -U postgres -F c -v -f "c:\tefh" -t
tefh -n art mdg

pg_dump then raises the following error:

'pg_dump: No matching tables were found'

I tried some alternatives from the command line, but pg_dump only seems to
make the single-table backup when the table name is qualified, as in:

pg_dump.exe -i -h localhost -p 5432 -U postgres -F c -v -f "c:\tefh" -t
art.tefh mdg

The command currently generated by pgadmin is not following a rule described
in the pg_dump documentation (the second note on the '-t' option) :

'you must write something like -t sch.tab to select a table in a particular
schema, rather than the old locution of -n sch -t tab'

Is there some known workaround to this problem ?
Thank you.

Hélder M. Vieira