Problematic line (line number 158 or something, depends on your Expose version):
$langcode = split('-',$conf->getValue('config.language'));
$langcode = preg_split('/-/',$conf->getValue('config.language'));
The issue cause is that split function is rated as deprecated in PHP 5.3.0+. Its replacement is preg_split, with slightly different syntax.
The problem exists in version Expose_4.6.3_Alpha3c bridge, which is from year 2009, and in the actual version for the moment of writing the article, September 2011.
Another problem in this release (also in PHP 5.3.0+) is in "System check" function. It shows an issue with JPEG/JPG support. The cause is described in PHP manual:
Previous to PHP 5.3.0, the JPEG Support attribute was named JPG Support.
The problem is only in "System check", all other functionality seems to work fine, so the indicated fatal error message could be ignored. But if you want to be clear, you could correct it in file:
Problematic line (line number 385 or something, depends on your Expose version):
"test" => ($array['JPG Support'] == true),
"test" => ($array['JPEG Support'] == true),
The false fatal error is:
JPG support disabled Fatal warning
⇒ Must be activated in php.ini for manipulating JPG type images. You probably need to ask your host to activate it.
The PHP warning is:
Notice: Undefined index: JPG Support in [joomla-root]/components/com_expose/expose/manager/check_system.php on line 385
Note: A fixed version of the module is available here.