There seems to be a rather peculiar error with the site. It started with me trying to alter the design (where i was going to place a search bar at the top of the site).
to do this i altered the Header.php in my design, the style.css and finally the general-template.php in the wp-includes folder.
The issues im having is that whenever the users of my blog log in , and subsequently visit the blog's homepage they get the following error (see here http://tinypic.com/r/14bqn1j/5 ). This is also the same when they try and preview a post. This is all quite bizarre as my login seems to work fine (however when visiting the users page in my dashboard, it appears blank)
Now, any changes i made yesterday, i have reverted. However the problem still persists.
i just wondered if u guys have experienced this before...
the site is http://TheCypher.co.uk and as u can see its working fine (all until i log in using one of my staffs logins)