So unless I've made a mistake in the formulas, any error must lie in the hub or rim measurements. Errors in ERD have a direct effect on spoke length. ERD is also the easiest to get wrong, since rims are rarely round when not built into wheels, and you may measure at a large or small diameter. It is definately worth measuring ERD at several locations around the rim and averaging. The idea is to reduce the effect of any single measurement falling at a high or low spot.
Many formulas ignore spoke hole diameter entirely.
You can always download a current copy of Spocalc or SpocalcExpress from this page. This will fix problems like accidentally typing over hub or rim dimensions on the database sheets, or typing over formulas on the calculator sheet. Hey Damon, I got the macros working. Go under Tools, Macros, then Security. Three option are there.