pgAdmin Error when trying to run a simple SELECT

HelloCan anyone help with an error I'm suddenly getting in PgAdmin II.

My problem is this: Whenever I try to run an SQL statement like:

SELECT * from refUSERS;

I get an error:

ERROR: Relation "refusers" does not exist.

I've tried other simple SELECT statements but get the same message.

I can't for the life of me understand what's changed.

I can use other databases using the same login credentials and login
procedures and the error does not occur when using them; it only seems
to occur with this particular database. I can 'see' the database fine in
the Menu Tree. I can drill down to the tables and I can see the table
data by clicking on the Sunglasses icon - I just can't seem to run a
basic query.

Can any one help/suggest anything at all? Do I need to prefix the table
name with something? (although I never had to before)

Brad.