Date Error

[sondriven]

Im getting a date error when i try to enter a date in a subform

"You cant assign a value to this object"

1. The object may be a control for a read only form
2. The object may be on a form that is in design mode
3. The value may be too large for this field.

I have the table for this field set to Date/Time - Formatted to short date. The input mask to short date.

I never received this error before.

Thanks for your help.