First of all, you're not deleting the row; you're removing it. Deleting a DataRow and removing it are two different things.

Second, why are you removing it and add it back if all you want to do is update it? If all you want to do is update it then that's all you should do.

Third, if you really must remove the row for some reason then the very error message you posted is already telling you what to do:
This row has been removed from a table and does not have any data. BeginEdit() will allow creation of new data in this row.
Do you want to create new data in that row? If so then do what it says and call BeginEdit.