portfolio upload problems

I am getting nowhere with uploading portfolio items. I have images in the gallery and so try to create a portfolio selecting say 3 or 5 images. These appear to upload correctly but then “viewing” produces this error message.

Catchable fatal error: Object of class WP_Error could not be converted to string in /home/snapdeci/public_html/snap-decision.eu/wp-content/themes/zippy/includes/class-breadcrumb.php on line 95