It seems that node_export_access_check() function is used in one of the file, but nowhere is defined.

See:

$ grep -R node_export_access_check .
./node_export/views/views_handler_field_node_link_export.inc:    if (!node_export_access_check($node)) {

Related:
http://drupal.stackexchange.com/questions/56704/error-in-adding-node-exp...