add columns into a table

Hi all,
I have a form what I can add columns up to 6.
I have created dynamic columns into table. When I click add columns until it reach 2, it is automatically add a new table and number location wil be added 2. But it is does not work.
 
I have spent 3 days to work on it but it is not working.
Pleas help.
 
Here is my code:
 
form1.screen17.table3b.BehaviousButtons.addColumn::click - (JavaScript, client)
var nCount = form1.screen17.table3b.Table3.HeaderRow._SCOL2.count;
 
if(nCount>0 && nCount<3){
form1.screen17.table3b.Table3.HeaderRow._SCOL2.addInstance(1);
form1.screen17.table3b.Table3.Row1._SCOL2.addInstance(1);
form1.screen17.table3b.Table3.Row2._SCOL2.addInstance(1);
form1.screen17.table3b.Table3.Row3._SCOL2.addInstance(1);
form1.screen17.table3b.Table3.Row4._SCOL2.addInstance(1);
form1.screen17.table3b.Table3.Row5._SCOL2.addInstance(1);
form1.screen17.table3b.Table3.Row6._SCOL2.addInstance(1);
form1.screen17.table3b.Table3.Row7._SCOL2.addInstance(1);
form1.screen17.table3b.Table3.Row8._SCOL2.addInstance(1);

}
else if(nCount>=3){
form1.screen17.table3b._Table3.addInstance(1);

}