Что делать

После того как я импотирую мир вылетает ошибка

FATAL ERROR in

action number 1

of  Step Event0

for object app:

string_length argument 1 incorrect type (undefined) expecting a String (YYGS)

############################################################################################

--------------------------------------------------------------------------------------------

called from - gml_Script_buffer_write_string (line 1)

called from - gml_Script_json_save_value (line 1)

called from - gml_Script_json_save_var (line 1)

called from - gml_Script_project_save_timeline (line 1)

called from - gml_Script_project_save_objects (line 1)

called from - gml_Script_project_save (line 21)

called from - gml_Script_project_backup (line 10)

called from - gml_Script_app_update_backup (line 3)

called from - gml_Script_app_event_step (line 21)

called from - gml_Object_app_Step_0 (line 0)