It looks all right, but don't forget to enable editing again if the checkbox isn't ticked.
MyTable_ds.allowEdit(MyTable.ChechBox == NoYes::No);
Although didn't you say that you wanted disable editing by unchecking the box? That would be the…
Might be, Might be this can help you, Delete your RDL from Reporting server and deploy report again. If this does not helps you, it needs serious debugging, inside AX.