gitlab backup restore aborting with error "relation not found"

Setting up a new server (Ubuntu 14.04) with gitlab-omnibus, I want to import my old gitlab-data. I followed the instructions in the readme and upgraded my old installation to 7.10.1 to match the new one.

After copying the backup to the correct location, stopping unicorn and sidekiq, setting owner of the backup file to git on the new server and running sudo gitlab-rake gitlab:backup:restore BACKUP=XXXXXX, I get

** Invoke gitlab:backup:restore (first_time)
** Invoke environment (first_time)
** Execute environment
** Execute gitlab:backup:restore
Unpacking backup ... done
** Invoke gitlab:backup:db:restore (first_time)
** Invoke environment
** Execute gitlab:backup:db:restore
Restoring database ...
Restoring PostgreSQL database gitlabhq_production ... ** Invoke gitlab:db:drop_all_tables (first_time)
** Invoke environment
** Execute gitlab:db:drop_all_tables
** Invoke gitlab:db:drop_all_postgres_sequences (first_time)
** Invoke environment
** Execute gitlab:db:drop_all_postgres_sequences
psql:/var/opt/gitlab/backups/db/database.sql:22: ERROR:  syntax error at or near "`"
LINE 1: DROP TABLE IF EXISTS `application_settings`;
                             ^

...


psql:/var/opt/gitlab/backups/db/database.sql:172: invalid command \'
psql:/var/opt/gitlab/backups/db/database.sql:1135: ERROR:  syntax error at or near "`"
LINE 1: INSERT INTO `events` VALUES (17,NULL,NULL,NULL,NULL,5,'2014-...
                    ^
[DONE]
done
** Invoke gitlab:backup:repo:restore (first_time)
** Invoke environment
** Execute gitlab:backup:repo:restore
Restoring repositories ...
rake aborted!
ActiveRecord::StatementInvalid: PG::Error: ERROR:  relation "projects" does not exist
LINE 1: SELECT  "projects".* FROM "projects"   ORDER BY "projects"."...
                                  ^
: SELECT  "projects".* FROM "projects"   ORDER BY "projects"."id" ASC LIMIT 1000
/opt/gitlab/embedded/service/gem/ruby/2.1.0/gems/activerecord-4.1.9/lib/active_record/connection_adapters/postgresql_adapter.rb:822:in `exec'

...

/opt/gitlab/embedded/service/gem/ruby/2.1.0/bin/rake:23:in `load'
/opt/gitlab/embedded/service/gem/ruby/2.1.0/bin/rake:23:in `<main>'
PG::Error: ERROR:  relation "projects" does not exist
LINE 1: SELECT  "projects".* FROM "projects"   ORDER BY "projects"."...
                                  ^
/opt/gitlab/embedded/service/gem/ruby/2.1.0/gems/activerecord-4.1.9/lib/active_record/connection_adapters/postgresql_adapter.rb:822:in `exec'

...

/opt/gitlab/embedded/service/gem/ruby/2.1.0/bin/rake:23:in `<main>'
Tasks: TOP => gitlab:backup:repo:restore

I'm still not sure whether this is a bug or a misconfiguration of the server. Maybe you could help me, understanding whats going on.

The database.sql seems to be fine. The gitlab:check only runs into the same error.