Problem In Data Grid

I'm using Visual Basic 6.0, Oracle 8, Seagate Crystal Reports 8.0. I'm using a datagrid.
I'm assigining a sql query to populate the datagrid. I'm connecting to oracle 8.
In my query when i use to_char and to_date function then that particular columns are
read only in grid. And also in my query if i use just blank spaces to create a
blank column and when i say addnew to the grid and write something to that
particular blank column then it generates error "Column is read only".

The Query Is :

str1="select ' ' flag, Table1.code, table1.name," & _
"to_char(table1.amt) from table1"
rs1.open str1,connection,adopendynamic,adlockbatchoptimistic

set datagrid.datasource=rs1

rs1.addnew
datagrid.columns(0)=chr(62) <-----------Here it gives error