is it ok to have multiple versions of jquery?
Try using the jquery multi module. Drupal core relies on specific versions of jquery, but this module allows you to control which environments use which version.
https://drupal.org/project/jqmulti

You shouldn't add jquery manually, nor should any modules. Drupal adds its own in core. Your errors may well be related, but that's hard to tell from the info you give. Do you know which module has added this?