This error is photo-related and usually implies that an invalid 'string' is stored as the pupils photo in the database. In the series that causes the error, go to Admin > Edit Pupils.

1) Click through each pupil record

2) For any pupils that DO NOT have a photo, go to Actions in the top right and choose Clear Photo

3) Otherwise, if you get an error when clicking on a particular pupil, either with or without a photo, go to Actions > Clear Photo

You may then need to re-import the affected pupils photos. This should resolve the error but please contact us if not.