Error on import

I am attempting to import a zip code database into a postgresql using
COPY.. but I am getting an error that the data type of the for longitude
doesn't match the table's data type (double precision)

'RROR:  copy: line 1, Bad float8 input format '-73.0456

Any help on why -73.0456 won't go in is appreciated. Thanks!

Sample line:

0501,HOLTSVILLE,SUFFOLK,NY,NEW
YORK,D,U,36103,516,EASTERN,40.8154,-73.0456

and the table definition:

   Column    |         Type          | Modifiers
-------------+-----------------------+-----------
 zipcode     | character(5)          |
 city        | character varying(28) |
 county      | character varying(25) |
 statecode   | character(2)          |
 statename   | character varying(75) |
 citytype    | character(1)          |
 zipcodetype | character(1)          |
 countyfips  | character(5)          |
 areacode    | character(3)          |
 timezone    | character varying(15) |
 latitude    | double precision      |
 longitude   | double precision      |