Oracle apex 5: New computations added to page throw ERR-1002

Question

In a page that was created a while back, everytime i add a new computation (give it some name) i get this error:

ERR-1002 Unable to find item ID for item "PROBA" in application "810".

Unexpected error, unable to find item name at application or page level.

Technical Info (only visible for developers)
is_internal_error: true
apex_error_code: WWV_FLOW.FIND_ITEM_ID_ERR
component.type: APEX_APPLICATION_PAGE_COMP
component.id: 79749128835570313
component.name: PROBA
error_backtrace:

----- PL/SQL Call Stack -----
  object      line  object
  handle    number  name
000007FFFC131638       641  package body APEX_050000.WWV_FLOW_ERROR
000007FFFC131638       709  package body APEX_050000.WWV_FLOW_ERROR
000007FFFC131638      1013  package body APEX_050000.WWV_FLOW_ERROR
000007FFFC2CDD00      2994  package body APEX_050000.WWV_FLOW_META_DATA
000007FFFC239CE0      1731  package body APEX_050000.WWV_FLOW_SESSION_STATE
000007FFFC160470        51  package body APEX_050000.WWV_FLOW_COMPUTATION
000007FFFC160470        98  package body APEX_050000.WWV_FLOW_COMPUTATION
000007FFFC160470       238  package body APEX_050000.WWV_FLOW_COMPUTATION
000007FFFC4566D8      4864  package body APEX_050000.WWV_FLOW
000007FFFC4566D8      4914  package body APEX_050000.WWV_FLOW
000007FFFC351EC8       173  procedure APEX_050000.F
000007FFFC344EA0         2  anonymous block

Any help on why this is happening?

Answer 1

Computations are done on ITEMS (either page or application ITEMS). What this error says is that you are missing the ITEM called "PROBA". Check the page or application items and see if that item exists.

Answer 2

The item name that can't be found is "PROBA".

You can query the APEX data dictionary for the source of the error. If you do a query in SQL Commands of:

select * from apex_application_page_comp 
 where application_id = 810 
   and computation_id = 79749128835570313

You'll find the source of the problematic computation.