Error creating a table

I am in pgAdmin, attempting to create a table in an existing database.
This table is normally created and deleted by software I have written (C#).
I get this kind of error when executing the CREATE TABLE script (which
is a copy of similarly named table):

NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index
"public_rowkey" for table "ABSTRACT-SERVER_runsheet"

ERROR:  relation "public_rowkey" already exists

********** Error **********

ERROR: relation "public_rowkey" already exists
SQL state: 42P07

I have looked for rowkey in the "public" schema, but find nothing.
What can be the problem?  What might I be doing wrong?  I'm not sure
what to do.

Dale