This is an error in one of your snippets. Unfortunately, snippet error messages are a bit ambiguous (I'll look at fixing this in a future version), so I can't tell you exactly which snippe. You will need to go through and find one which uses
preg_replace() in its code.
If you don't want to click through editing each snippet to find the guilty one, you can login to your database phpMyAdmin and look at the
snippets table (it will be prepended with your WordPress database prefix). There you will be able to see all of the snippets and their code on the same page so you can find out the name of the snippet you need to edit.