Atahualph not working since PHP5 migration

I have just had my webspace migrated to PHP5, and now Atahualpa theme doesn't work. My webspace provider is Easyspace - just in case that's relevant.

This is the first error message at the top of my pages "Warning: include(): Failed opening 'bfa://html_inserts_body_top' for inclusion (include_path='.:/usr/share/pear:/usr/share/php') in /vhost/vhost9/m/a/n/mansheadschool.co.uk/test/wp-content/themes/atahualpa364/header.php on line 22
Warning: include(): Failed opening 'bfa://configure_header' for inclusion (include_path='.:/usr/share/pear:/usr/share/php') in /vhost/vhost9/m/a/n/mansheadschool.co.uk/test/wp-content/themes/atahualpa364/header.php on line 39 "

I've tried restoring from my backup, resetting all the settings back to default. Deleting and re-installing a fresh copy of Atahualpa, including deleting it and installing the newest version.

Any suggestions? Otherwise I will have to abandon using it, which would be a great shame.

Any help would be much appreciated.

Joanne