Error during backup

After hitting on “Run now” I have received the following errors:
[02-Mar-2013 10:08:50] PHP Fatal error: Call to undefined method mysqli::get_charset() in /wp-content/plugins/backwpup/inc/class-mysqldump.php on line 196
[02-Мар-2013 20:08:50] 3. Script stopped! Will start again.
[02-Мар-2013 20:08:50] 1. Trying to create backup archive …
[02-Мар-2013 20:08:50] Compression method is ZipArchive
[02-Мар-2013 20:08:50] Backup archive created.
[02-Мар-2013 20:08:50] WARNING: filesize(): stat failed for wp-content/uploads/backwpup-921bb-temp/backwpup_1_2013-03-02_20-08-49.zip
[02-Мар-2013 20:08:50] 0 Files with in Archive.
[02-Мар-2013 20:08:51] 1. Try to send backup with email …
[02-Мар-2013 20:08:51] Sending email to xxxxxxxxx@mail.ru …
[02-Мар-2013 20:08:51] WARNING: fopen(/wp-content/uploads/backwpup-921bb-temp/backwpup_1_2013-03-02_20-08-49.zip): failed to open stream: No such file or directory
[02-Мар-2013 20:08:51] ERROR: Swift Mailer: Unable to open file for reading [/wp-content/uploads/backwpup-921bb-temp/backwpup_1_2013-03-02_20-08-49.zip]
[02-Мар-2013 20:08:51] ERROR: Error while sending email!
[02-Мар-2013 20:08:52] 2. Try to send backup with email …
[02-Мар-2013 20:08:52] Sending email to xxxxxxxxx@mail.ru …
[02-Мар-2013 20:08:52] WARNING: fopen(/wp-content/uploads/backwpup-921bb-temp/backwpup_1_2013-03-02_20-08-49.zip): failed to open stream: No such file or directory
[02-Мар-2013 20:08:52] ERROR: Swift Mailer: Unable to open file for reading [/wp-content/uploads/backwpup-921bb-temp/backwpup_1_2013-03-02_20-08-49.zip]
[02-Мар-2013 20:08:52] ERROR: Error while sending email!
[02-Мар-2013 20:08:53] 3. Try to send backup with email …
[02-Мар-2013 20:08:53] Sending email to xxxxxxxxx@mail.ru …
[02-Мар-2013 20:08:53] WARNING: fopen(/wp-content/uploads/backwpup-921bb-temp/backwpup_1_2013-03-02_20-08-49.zip): failed to open stream: No such file or directory
[02-Мар-2013 20:08:53] ERROR: Swift Mailer: Unable to open file for reading [/wp-content/uploads/backwpup-921bb-temp/backwpup_1_2013-03-02_20-08-49.zip]
[02-Мар-2013 20:08:53] ERROR: Error while sending email!
[02-Мар-2013 20:08:54] One old log deleted
[02-Мар-2013 20:08:54] Job done in 5 seconds.
What can i do? Could you please explain by steps?
Thank you in advance.
Alex

http://wordpress.org/extend/plugins/backwpup/