setting LongReadLen

[Corey Smith (s)]

I'm using Perl v5.6.1 on NT with DBI version 1.16, and am trying to do a
select on a LONG RAW column.  As I understand it the default setting of
LongReadLen is 0.  The error I get is :  

DBD::Oracle::st fetchrow_array failed: ORA-01406: fetched column value was
truncated (DBD: ORA-01406 error on field 3 of 3, ora_type 24, DBI attribute
Long
TruncOk not set and/or LongReadLen too small) at tde_generalDBI_2.pl line
15.

I then tried setting LongReadLen like this:
        $dbh = DBI->connect('dbi:Oracle:','username','password') or die;
        $dbh -> LongReadLen(400);

            $sth = $dbh -> prepare('SELECT * FROM .......');
            $sth -> execute();

I'm getting the following error when I execute the above code:

    Can't locate object method "LongReadLen" via package "DBI::db" (perhaps
you forgot to load "DBI::db"?) at       tde_generalDBI_2.pl line 10.

I'm stuck.  How do I reset LongReadLen? Any help would be greatly
appreciated.  Thanks in advance.

Corey