Views not found on disabling Page Title module
The page_titles module sets a lot of variables. I don't know if that would cause an issue like you are seeing, but it's best to remove these variables. Disabling the module will not remove them, but uninstalling it will. With page_title disabled, go to admin/modules/uninstall, select the module, and click uninstall. This will unset all variables that were set by the module.