combobox in datagrid

I am trying to add a combobox in a datagrid. I have tried using the example that is found on this website but it doesnt work. It works when it is compiled separately as its own project, but when it is added to my project as a child form it gives me an error at runtime: "Input string was not in a correct format". The line that is triggering the error is "Combo.SelectedValue = GetText(GetColumnValueAtRow(Source, Rownum));" in the sjDataGridComboBox.cs file. If I catch the exception and dont do anything it just leaves the int32 value and not the text value that I want. If anybody has experience using this and got it to work, let me know and give me some ideas. If there is another way to do it let me know. Thanks,