problem with parsing GPML

For the following files conversion to SBML returns 400:

ls *.gpml | while read x; do echo $x; curl 'https://minerva-service.lcsb.uni.lu/minerva/api/convert/GPML:SBML' -s -w "%{http_code}"  -X POST     --data-binary @$x -o $x.tmp; echo; done

• WP4853.gpml
• WP4868.gpml
• WP4876.gpml
• WP4880.gpml
• WP4927.gpml
• WP5027.gpml
• WP5113.gpml
• WP5183.gpml
• WP5218.gpml

reported by @egonw