Mensaje de error al finalizar aplicacion

[salvanano]

El problema viene cuando manejo una tabla determinada (table12), mientras no toque ese tabla el programa no da ningun problema, por lo que os dejo aqui el codigo donde manipulo dicha tabla a ver si ustedes son capaces de ver el fallo. A mi me trae de cabeza.
Saludos

Código Delphi [-]
procedure TForm17.Button1Click(Sender: TObject);
begin
//coloco la fecha en su campo
DBEdit9.Text:= DateToStr(Date);
table10.Post;
// Registro en la tabla auxiliar para imprimir después
if dblookupcombobox1.Text<>'' then
begin
Table1.IndexFieldNames:= 'DESCRIPCION';
if Table1.FindKey([DBLooKupComboBox1.Text])=True then
Table12.Edit;
Table12.FieldByName('CANTIDAD').AsFloat:= StrToFloat(Form17.Edit6.Text);
Table12.FieldByName('DESCRIPCION').AsString:= Table1.FieldByName('DESCRIPCION').AsString;
Table12.FieldByName('PRECIO').AsFloat:= Table1.FieldByName('PRECIO').AsFloat;
Table12.FieldByName('SUBTOTAL').AsFloat:= Table1.FieldByName('PRECIO').AsFloat * StrToFloat(Form17.Edit6.Text);
end;
//-------------------------------------------------------------
if dblookupcombobox2.Text<>'' then
begin
Table2.IndexFieldNames:= 'DESCRIPCION';
if Table2.FindKey([DBLooKupComboBox2.Text])=True then
Table12.Insert;
Table12.FieldByName('CANTIDAD').AsFloat:= StrToFloat(Form17.Edit7.Text);
Table12.FieldByName('DESCRIPCION').AsString:= Table2.FieldByName('DESCRIPCION').AsString;
Table12.FieldByName('PRECIO').AsFloat:= Table2.FieldByName('PRECIO').AsFloat;
Table12.FieldByName('SUBTOTAL').AsFloat:= Table2.FieldByName('PRECIO').AsFloat * StrToFloat(Form17.Edit7.Text);
end;
//-------------------------------------------------------------
if dblookupcombobox3.Text<>'' then
begin
Table3.IndexFieldNames:= 'DESCRIPCION';
if Table3.FindKey([DBLooKupComboBox3.Text])=True then
Table12.Insert;
Table12.FieldByName('CANTIDAD').AsFloat:= StrToFloat(Form17.Edit8.Text);
Table12.FieldByName('DESCRIPCION').AsString:= Table3.FieldByName('DESCRIPCION').AsString;
Table12.FieldByName('PRECIO').AsFloat:= Table3.FieldByName('PRECIO').AsFloat;
Table12.FieldByName('SUBTOTAL').AsFloat:= Table3.FieldByName('PRECIO').AsFloat * StrToFloat(Form17.Edit8.Text);
end;
//-------------------------------------------------------------
if dblookupcombobox4.Text<>'' then
begin
Table4.IndexFieldNames:= 'DESCRIPCION';
if Table4.FindKey([DBLooKupComboBox4.Text])=True then
Table12.Insert;
Table12.FieldByName('CANTIDAD').AsFloat:= StrToFloat(Form17.Edit9.Text);
Table12.FieldByName('DESCRIPCION').AsString:= Table4.FieldByName('DESCRIPCION').AsString;
Table12.FieldByName('PRECIO').AsFloat:= Table4.FieldByName('PRECIO').AsFloat;
Table12.FieldByName('SUBTOTAL').AsFloat:= Table4.FieldByName('PRECIO').AsFloat * StrToFloat(Form17.Edit9.Text);
end;
//-------------------------------------------------------------
if dblookupcombobox5.Text<>'' then
begin
Table5.IndexFieldNames:= 'DESCRIPCION';
if Table5.FindKey([DBLooKupComboBox5.Text])=True then
Table12.Insert;
Table12.FieldByName('CANTIDAD').AsFloat:= StrToFloat(Form17.Edit10.Text);
Table12.FieldByName('DESCRIPCION').AsString:= Table5.FieldByName('DESCRIPCION').AsString;
Table12.FieldByName('PRECIO').AsFloat:= Table5.FieldByName('PRECIO').AsFloat;
Table12.FieldByName('SUBTOTAL').AsFloat:= Table5.FieldByName('PRECIO').AsFloat * StrToFloat(Form17.Edit10.Text);
end;
//-------------------------------------------------------------
if dblookupcombobox6.Text<>'' then
begin
Table6.IndexFieldNames:= 'DESCRIPCION';
if Table6.FindKey([DBLooKupComboBox6.Text])=True then
Table12.Insert;
Table12.FieldByName('CANTIDAD').AsFloat:= StrToFloat(Form17.Edit11.Text);
Table12.FieldByName('DESCRIPCION').AsString:= Table6.FieldByName('DESCRIPCION').AsString;
Table12.FieldByName('PRECIO').AsFloat:= Table6.FieldByName('PRECIO').AsFloat;
Table12.FieldByName('SUBTOTAL').AsFloat:= Table6.FieldByName('PRECIO').AsFloat * StrToFloat(Form17.Edit11.Text);
end;
//-------------------------------------------------------------
if dblookupcombobox7.Text<>'' then
begin
Table7.IndexFieldNames:= 'DESCRIPCION';
if Table7.FindKey([DBLooKupComboBox7.Text])=True then
Table12.Insert;
Table12.FieldByName('CANTIDAD').AsFloat:= StrToFloat(Form17.Edit12.Text);
Table12.FieldByName('DESCRIPCION').AsString:= Table7.FieldByName('DESCRIPCION').AsString;
Table12.FieldByName('PRECIO').AsFloat:= Table7.FieldByName('PRECIO').AsFloat;
Table12.FieldByName('SUBTOTAL').AsFloat:= Table7.FieldByName('PRECIO').AsFloat * StrToFloat(Form17.Edit12.Text);
end;
//-------------------------------------------------------------
if dblookupcombobox8.Text<>'' then
begin
Table8.IndexFieldNames:= 'DESCRIPCION';
if Table8.FindKey([DBLooKupComboBox8.Text])=True then
Table12.Insert;
Table12.FieldByName('CANTIDAD').AsFloat:= StrToFloat(Form17.Edit13.Text);
Table12.FieldByName('DESCRIPCION').AsString:= Table8.FieldByName('DESCRIPCION').AsString;
Table12.FieldByName('PRECIO').AsFloat:= Table8.FieldByName('PRECIO').AsFloat;
Table12.FieldByName('SUBTOTAL').AsFloat:= Table8.FieldByName('PRECIO').AsFloat * StrToFloat(Form17.Edit13.Text);
end;
//-------------------------------------------------------------
if dblookupcombobox9.Text<>'' then
begin
Table9.IndexFieldNames:= 'DESCRIPCION';
if Table9.FindKey([DBLooKupComboBox9.Text])=True then
Table12.Insert;
Table12.FieldByName('CANTIDAD').AsFloat:= StrToFloat(Form17.Edit14.Text);
Table12.FieldByName('DESCRIPCION').AsString:= Table9.FieldByName('DESCRIPCION').AsString;
Table12.FieldByName('PRECIO').AsFloat:= Table9.FieldByName('PRECIO').AsFloat;
Table12.FieldByName('SUBTOTAL').AsFloat:= Table9.FieldByName('PRECIO').AsFloat * StrToFloat(Form17.Edit14.Text);
end;
end;