nextval problem

I'm new to postgresql and I'm having problems with the 'nextval' function
(or whatever it is called in postgresql).

I created a table (called ADDRESS) using 'pgadmin' which has a serial field
(called addressid). When I tried the sql statement:

select nextval('public."ADDRESS_addressid_seq"')

everything seemed to be working fine.

I then used the create table statement (displayed in pgadmin when the table
'ADDRESS' is selected) to create the same table (of course after first
dropping 'ADDRESS'). When I try the same select-statement I suddenly got an
error message saying:

ERROR: Relation "public"."ADDRESS_addressid_seq" does not exist

Can anybody help me with this problem?