How to enable jEditable to perform updates?
Consider looking at the Editable Views module for a possible alternative. Here is a quote about it from its project page:

... lets you create Views where the fields can be edited. Fields show both the current value and a form to edit it. A 'Save' button allows saving of all the entities shown in the View.
Editable fields can be added on the base entity as well as on entities brought into the View by a relationship. Other, non-editable fields may be added to the View, in which case they function normally.
Currently, the following Views fields can be edited:

all FieldAPI fields
node title