You may need to change the owner of the budget process. This is easily done within Jet Budgets.
The current owner, an Admin user, or any other user to whom Budget Owner permissions have been granted and who has access to the underlying data source can be assigned as the owner of a Jet budget.
From Jet Budgets, right-click the budget you want to modify and select Change Owner
The current owner will be displayed and the Select New Owner pulldown will include the name of Admin and Budget Owner users
Select the new owner from the list and then click the Change Owner button
If the selected new owner does not have access to the budget's underlying data source, a message will be displayed.
Either select a different owner or have an Admin user provide that user with the necessary access