'you have an error in your SQL sintax. Check the manual that corresponds to your mysql server version for the right sintax to use near "at line '.

When eqsaldo=0 (zero) I receive this message.

procedure transac.movimento;
begin
tabelas.THist.Open;
tabelas.THist.Insert;
tabelas.THistsaldoqtd.Value := eqsaldo;
tabelas.Thist.Post;
tabelas.Thist.Close;
end;

"tabelas' is Data Module and "Thist" is a Delphi object TTable.
When eqsaldo > 0 (zero) no problem: eqsaldo value is corretly inserted into table.
I use Wamp server with MySQL 5.5.8. and Delphi 7.

The table"s structure is:
CREATE TABLE IF NOT EXISTS `histacoes` (
`id` int(4) NOT NULL AUTO_INCREMENT,
`titular` varchar(8) NOT NULL,
`ativo` varchar(8) NOT NULL,
`data` date NOT NULL DEFAULT '0000-00-00',
`nota` varchar(8) NOT NULL,
`agente` varchar(10) NOT NULL,
`hist` varchar(4) NOT NULL,
`quant` int(11) NOT NULL DEFAULT '0',
`cota` decimal(10,2) NOT NULL DEFAULT '0.00',
`vrativo` decimal(10,2) NOT NULL DEFAULT '0.00',
`corret` float(10,2) NOT NULL DEFAULT '0.00',
`emol` decimal(8,2) NOT NULL DEFAULT '0.00',
`vrliquidocompra` float(10,2) NOT NULL,
`saldocompras` float(10,2) NOT NULL,
`vrliquidovenda` float(10,2) NOT NULL,
`precomedio` float(10,2) NOT NULL,
`custodia` decimal(8,2) NOT NULL DEFAULT '0.00',
`taxas` decimal(4,2) NOT NULL DEFAULT '0.00',
`baseir` decimal(10,2) NOT NULL DEFAULT '0.00',
`ir` decimal(10,2) NOT NULL DEFAULT '0.00',
`saldoqtd` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=15 ;

Please help me.
Tks