Overlapping Tags message
This message comes up when the content of one field overlaps the content of another field, regardless of whether a field was deleted or changed after its original creation.
To work around the error, select content/HTML that is after the overlapping region but before the next field, regardless if this is the actual content you want in the field. Try selecting HTML/content of at least 1/10th the size of the actual content/HTML you want (if you can't you will need to change the column length in the Field Properties->Database tab->Column Length. Keep in mind that this value resets itself based on the original content length every time a new field in this dataset is created. So create all your fields, then go back and fix column lengths.)
Once the field is created, you can change the tags in Field Properties->Tags(Manual) tab, to get the actual content you want.
The alternative to this is to recreate the datapage, getting the fields right on creation.