Hi Thomas,
I assume you have the following config enabled :
apoc.import.file.enabled=true
By default file paths are relative to the import directory. If you want to use absolute paths, you need to add the following config :
apoc.import.file.use_neo4j_config=false
As your file seems to be in the "import" directory already : call apoc.import.xml("file:///FODS_Person.xml") should also do.
But I'd still expect a "FileNotFound" rather than a "NullPointer", so there may be something else going on. Any stack trace from the log?
Regards,
David