Any chance that this is a a db rights issue or issue with db space of physical disc space?.
So you create a custom object.
and it has the list view and the view has fields?
Do you see the Custom objects group in the menu manager and do you see the custom object list view there?
Do you see the Custom objects group in the app?
Are the pages created in the db for the custom object?
Are they active, default, system etc?
Are the menu items created in the db for the custom object?
Are the respective actions created?
Anyway it is not possible to delete the custom object list page erroneously.