Data-conversion resulted in overflow using FreeTDS and SQLServer

We are using freetds 0.82 to connect to a MSQL database 2005.

When reading certain tables, using fisql, we have no errors but other 
tables give
the error:

error_handler: Data-conversion resulted in overflow.
for each line of results.

If I use DBArtisan on this database this does not occur.

Could someone please advise possible cause of error and how we might fix 
it.

The table where we have an error is pretty standard as follows:

CREATE TABLE PHONE_FAX
(
        ID          varchar(4)   COLLATE SQL_Latin1_General_CP1_CS_AS NOT 
NULL,
     ID_USER      varchar(9)   COLLATE SQL_Latin1_General_CP1_CS_AS NOT 
NULL,
     OR_PHONE     numeric(6,0) NOT NULL,
     DT_START     datetime     NULL,
     DT_END       datetime     NULL
     PRIMARY KEY CLUSTERED (ID_USER,OR_PHONE,ID)
)


Thanks.

Daymel