A friend of mine has just moved their website to a new hosting company. Since then they are not received emails submitted via a contact form but are getting the message
"WordPress database error You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'AND post_type='page'' at line 1 for query SELECT ID FROM wp_posts WHERE post_parent = AND post_type='page' made by require, require_once, include, get_header, locate_template, load_template, require_once, getMaxPossibleDepth."
The entire contents of the original website were put into a Tarball and transferred across including all of the databases so everything should be exactly the same.
They have asked me to take a look as I know a bit about IT stuff but haven't touched Wordpress before although am interested in developing more of a knowledge of it.
Any suggestions anyone?