It sounds like you might already be doing this, but here is the code I used to get around a similiar CLOB issue...

my $dbh = DBI->connect("DBI:Oracle:", "$login\@$sid", $pass);
die "Couldn't connect to Oracle: $!" unless $dbh;
$dbh->{LongReadLen} = 66000;
$dbh->{LongTruncOk} = 1;
[download]

-Blake