Ajax Search won't let page load

I’m trying AjaxSearch for the first time without parameters and it causes a blank page to load.

Client side operating system and browser type: Windows XP SP3 - IE8 and Firefox 3.5
modx version: evolution 1.0.2
Php version: PHP Version 5.1.6
MySql version: 5.0.77
ajaxSearch snippet version: 1.8.4
ajaxSearch snippet call of the page where is the search form: [!AjaxSearch!]
charset of html page: iso-8859-1
charset of database: UTF-8 Unicode (utf8)
value of your $database_connection_charset variable in /manager/includes/config.inc.php file: latin1
If I activate debug mode:

[18-Feb-10 10:26:27] AjaxSearch - Php5.1.6 - MySql 5.0.77
[18-Feb-10 10:26:27] AjaxSearch - User configuration - Before parameter checking : Array
(
[config] =>
[debug] => 3
[language] => english
[ajaxSearch] => 1
[advSearch] => oneword
[whereSearch] => content|tv
[subSearch] => 5,1
[withTvs] =>
[order] => publishedon,pagetitle
[rank] => pagetitle:100,extract
[maxWords] => 5
[minChars] => 3
[AS_showForm] => 1
[resultsPage] => 0
[grabMax] => 10
[extract] => 1:content,description,introtext,tv_value
[extractLength] => 200
[extractEllips] => ...
[extractSeparator] =>

[formatDate] => d/m/y : H:i:s
[highlightResult] => 1
[pageLinkSeparator] => |
[showPagingAlways] => 0
[AS_landing] =>
[AS_showResults] => 1
[parents] =>
[documents] =>
[depth] => 10
[hideMenu] => 2
[hideLink] => 1
[filter] =>
[tplLayout] => @FILE:assets/snippets/ajaxSearch/templates/layout.tpl.html
[tplResults] => @FILE:assets/snippets/ajaxSearch/templates/results.tpl.html
[tplResult] => @FILE:assets/snippets/ajaxSearch/templates/result.tpl.html
[tplComment] => @FILE:assets/snippets/ajaxSearch/templates/comment.tpl.html
[tplPaging] => @FILE:assets/snippets/ajaxSearch/templates/paging.tpl.html
[stripInput] => defaultStripInput
[stripOutput] => defaultStripOutput
[searchWordList] =>
[breadcrumbs] =>
[tvPhx] =>
[clearDefault] => 0
[jsClearDefault] => assets/snippets/ajaxSearch/js/clearDefault.js
[mbstring] => 1
[asLog] => 0:0:200
[liveSearch] => 0
[ajaxMax] => 6
[showMoreResults] => 0
[moreResultsPage] => 0
[opacity] => 1
[tplAjaxResults] => @FILE:assets/snippets/ajaxSearch/templates/ajaxResults.tpl.html
[tplAjaxResult] => @FILE:assets/snippets/ajaxSearch/templates/ajaxResult.tpl.html
[jscript] => mootools
[addJscript] => 1
[jsMooTools] => manager/media/script/mootools/mootools.js
[jsMooTools1.2] => assets/snippets/ajaxSearch/js/mootools1.2/mootools.js
[jsJquery] => assets/snippets/ajaxSearch/js/jQuery/jquery.js
)

[18-Feb-10 10:26:27] AjaxSearch - Search string :

charset of html page: iso-8859-1
charset of database: UTF-8 Unicode (utf8)
value of your $database_connection_charset variable in /manager/includes/config.inc.php file: latin1

Your html page charset should be coherent with your database charset and with your database_connection_charset. All should be UTF-8/utf8 or iso-8859-1/latin1

Ok thanks. I set all of the charsets to utf8. Now I get a search box. But my search results say "php_mbstring extension required" after I click "Go!" even though I also set &mbstring=`0`. If I set &mbstring=`1` I still get a blank page.

I found another thread about this. Seems centOS and ajaxsearch have some issues.

If I set &mbstring=`0` and &ajaxSearch=`0` I get the following php error:

PHP error debug
Error: preg_replace() [function.preg-replace]: Compilation failed: lookbehind assertion is not fixed length at offset 11
Error type/ Nr.: Warning - 2
File: /home/public_html/manager/includes/document.parser.class.inc.php(746) : eval()’d code

Seems centOS and ajaxsearch have some issues.

Yes the better workaround for you is to use the previous version of the highlighting plugin (1.3)
You can download this version of this plugin by downloading the release 1.8.1 of AjaxSearch