ODP.NET

I have a strange problem in my application.
I install the application on several machines with no problem but in one machine I'm getting an exceptions on:
"Column 'SomeColumnName' does not belong to table"
the code look like this:
DataRow newDataRow = myTableFromDatabase.NewRow();
newDataRow["SomeColumnName"] = dr["SomeColumnName"];

when I change the code to upper case:
DataRow newDataRow = myTableFromDatabase.NewRow();
newDataRow["SOMECOLUMNNAME"] = dr["SOMECOLUMNNAME"];

it works on the problematic machine.

- I got the same problem on reading data from OracleDataReader.

- The property DataTable.CaseSensitive was not changed (default = false).

I'm not sure this is ODP problem or .net but I can't find any .net issues on that.