PHP error on wordpress site

Hello guys, i’m a web designer with very limited knowledge of PHP, i designed a wordpress site for a client and i think they must have installed a plugin that is causing some errors on the site, it has even disabled the slider, how can i detect this error?

thanks guys.

[FONT=Georgia]Hi i_r_maximus.

What’s the error message you’re getting?

Also, do you have access to the web hosts? It’s possible that the host updated the default version of PHP on their servers, which could cause some errors too.[/FONT]

Warning: Illegal string offset ‘id’ in /home/brandiq/public_html/wp-content/themes/brandiQ_mag/header.php on line 4

thats the error msg

Please post the first several lines of the header.php file.