Error on database update

When I run the update.php from site building > modules
(mysite.com/update.php)

I get the following error:

"An unrecoverable error has occurred. You can find the error message below. It is advised to copy it to the clipboard for reference.
Please continue to the error page
An error occurred. www.mysite.com/update.php?id=9&op=do
Fatal error: Call to undefined function _system_update_utf8() in /sites/all/modules/webform/webform.install on line 384
"

"The update process was aborted prematurely while running update #3 in webform.module. "