please help me how can i repair this problem.... thx

Parse error: syntax error, unexpected '<' in /www/zxq.net/w/a/l/walterjr/htdocs/libraries/joomla/utilities/string.php on line 891

something must be wrong, the max line of the file string.php is only 446, there is no the line 891.

i change the string.php then the problem change to this.
Warning: require_once() [function.require-once]: Unable to access /www/zxq.net/w/a/l/walterjr/htdocs/libraries/phputf8/utf8.php in /www/zxq.net/w/a/l/walterjr/htdocs/libraries/joomla/utilities/string.php on line 40

Warning: require_once(/www/zxq.net/w/a/l/walterjr/htdocs/libraries/phputf8/utf8.php) [function.require-once]: failed to open stream: No such file or directory in /www/zxq.net/w/a/l/walterjr/htdocs/libraries/joomla/utilities/string.php on line 40

Fatal error: require_once() [function.require]: Failed opening required '/www/zxq.net/w/a/l/walterjr/htdocs/libraries/phputf8/utf8.php' (include_path='.:/usr/lib/php') in /www/zxq.net/w/a/l/walterjr/htdocs/libraries/joomla/utilities/string.php on line 40


how can i resolve this kind of problem