Hi.
I have one account hosted in the server having the following error. I recompile the server apache by adding mod_ruid + jailshell.
account - forum.engkabang.net
2: preg_replace() [<a href='function.preg-replace'>function.preg-replace</a>]: Compilation failed: unknown option bit(s) set at offset -1
File: /home/ekabang/public_html/forum/Sources/Subs.php
Line: 2531
Does such error related to apache recompile?
(https://www.simplemachines.org/community/proxy.php?request=http%3A%2F%2Fwww.katzy.dsl.pipex.com%2FSMF%2Fwelcome.gif&hash=64d0bdab41bf056c5af638442124afd2cc58a5fb)
On the page that you downloaded the mod from, you'll see this:
(https://www.simplemachines.org/community/proxy.php?request=http%3A%2F%2Fwww.katzy.dsl.pipex.com%2FSupportComments.gif&hash=eee22bcbe815f431a7f8cc4fedf319328bba6d6c)
If you click that, you'll be taken to the mod's support topic, where they'll be able to help you, with this.
:)
Google shows some related problems (not with SMF, but with other PHP scripts) and some solutions.
Have a look:
http://labs.sasslantis.ee/2011/05/errors-in-wordpress-after-php-upgrade/
https://bugs.dokuwiki.org/index.php?do=details&task_id=2228
(everyone seems to blame a certain PCRE, whatever that is :P )
So, it seems this error is likely due to an older version of the pcre library (pcre = perl-compatible regular expressions). If you're using mod_php, it gets loaded inside Apache httpd and possibly could be pulling an older version because of that.
How did you do the recompile of the service? Is this part of cPanel, or are you manually loading things on your server?