Code Error when saving edits to a project

[jeffreyover9000 0]

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FATAL ERROR in
action number 1
of Draw Event
for object app:

unable to convert string "" to number
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called from - gml_Script_save_id_get (line 7)
called from - gml_Script_json_save_var_save_id (line 30)
called from - gml_Script_project_save_timeline (line 41)
called from - gml_Script_project_save_objects (line 15)
called from - gml_Script_project_save (line 22)
called from - gml_Script_project_save_as (line 44)
called from - gml_Script_popup_saveas_draw (line 42)
called from - gml_Script_popup_draw (line 111)
called from - gml_Script_window_draw (line 28)
called from - gml_Script_app_event_draw (line 8)
called from - gml_Object_app_Draw_0 (line 1)