OK. Looks like your hosting provider has disabled the ini_set() function for security reasons. This was necessary to add dataface and dataface/lib to your include path. This seems like a pretty tight security restriction. I have worked with quite a few shared hosts and haven't run into one that disables this function. However a quick search on Google for this error indicates that there do exist hosts that disable it.
It might be worth checking with your host to see if they can enable this function. They may not be aware that it is disabled right now. Note that this is not a safe mode restriction. ini_set() is allowed in safe mode, which is the mode used by most web hosts.
See
http://www.php.net/manual/en/features.safe-mode.functions.php for information about safe mode limitations.
In case the host is unaware of this function being disabled, it is likely disabled in the php.ini file using the "disable_functions" directive.
See
http://www.php.net/manual/en/features.safe-mode.php#ini.safe-mode-include-dir and do a find for "disable_functions" for information about this directive.
If they are unwilling to remove this restriction, it will be difficult to get around this, because dataface absolutely needs to have the dataface and dataface/lib directories in the include path. It is also supposed to be possible to set the include paths from an .htaccess file but it is common for this feature to be disabled.
i.e., your best bet is to get your host to un-disable the ini_set() function or find a new host.
Hope this helps a little.
Best regards
Steve Hannah