Registration of invited user

Send invitation using using Invite module, when an invited user goes to url given in invitation mail get this error:

Notice: Undefined index: #user_category in user_relationship_mailer_form_alter() (line 187 of /home/memory/public_html/modules/user_relationships/user_relationship_mailer/user_relationship_mailer.module).
Notice: Undefined index: #user_category in user_relationship_mailer_form_alter() (line 187 of /home/memory/public_html/modules/user_relationships/user_relationship_mailer/user_relationship_mailer.module).
Notice: Undefined index: #user_category in user_relationship_privatemsg_form_alter() (line 311 of /home/memory/public_html/modules/user_relationships/user_relationship_privatemsg/user_relationship_privatemsg.module).
Notice: Undefined index: #parents in form_builder() (line 1713 of /home/memory/public_html/includes/form.inc).
Warning: implode() [function.implode]: Invalid arguments passed in form_builder() (line 1713 of /home/memory/public_html/includes/form.inc).
Notice: Undefined index: #tree in form_builder() (line 1743 of /home/memory/public_html/includes/form.inc).
Notice: Undefined index: #array_parents in form_builder() (line 1766 of /home/memory/public_html/includes/form.inc).
Notice: Undefined index: process_input in _form_builder_handle_input_element() (line 1904 of /home/memory/public_html/includes/form.inc).
Notice: Undefined index: complete form in form_builder() (line 1723 of /home/memory/public_html/includes/form.inc).
Notice: Undefined index: process_input in _form_builder_handle_input_element() (line 1904 of /home/memory/public_html/includes/form.inc).
Notice: Undefined index: complete form in form_builder() (line 1723 of /home/memory/public_html/includes/form.inc).
Notice: Undefined index: process_input in _form_builder_handle_input_element() (line 1904 of /home/memory/public_html/includes/form.inc).
Notice: Undefined index: complete form in form_builder() (line 1723 of /home/memory/public_html/includes/form.inc).
Notice: Undefined index: #tree in form_builder() (line 1743 of /home/memory/public_html/includes/form.inc).
Notice: Undefined index: #array_parents in form_builder() (line 1766 of /home/memory/public_html/includes/form.inc).
Notice: Undefined index: process_input in _form_builder_handle_input_element() (line 1904 of /home/memory/public_html/includes/form.inc).
Notice: Undefined index: #tree in form_builder() (line 1743 of /home/memory/public_html/includes/form.inc).
Notice: Undefined index: #array_parents in form_builder() (line 1766 of /home/memory/public_html/includes/form.inc).
Notice: Undefined index: process_input in _form_builder_handle_input_element() (line 1904 of /home/memory/public_html/includes/form.inc).
Notice: Undefined index: #tree in form_builder() (line 1743 of /home/memory/public_html/includes/form.inc).
Notice: Undefined index: #array_parents in form_builder() (line 1766 of /home/memory/public_html/includes/form.inc).
Notice: Undefined index: process_input in _form_builder_handle_input_element() (line 1904 of /home/memory/public_html/includes/form.inc).
Notice: Undefined index: process_input in drupal_process_form() (line 817 of /home/memory/public_html/includes/form.inc).