images : Catchable fatal error

hi all

i develop a local site with WP 3.5.1 FR
when i click on an image from a gallery for example, i’ve this error :

Catchable fatal error: Object of class WP_Error could not be converted to string in C:\wamp\www\bleu213\wp-content\themes\lugada\include\breadcrumbs.php on line 74

it’s very embarrassing because it’s already the second theme (responsive) tested.

when i do a search on google, many site have this error on their page…

Please help me : must i change the theme or maybe a little key in page is possible ?

thanks a lot

Isabelle
France