So you have a lovely LDIF file of Active Directory schema that you want to import using the ldbmodify tool provided with Samba4... but when you attempt the import it fails with the error:
Error: First line of ldif must be a dn not 'dn'
Modified 0 records with 0 failures
Eh? @&^$*&;@&^@! It does start with a dn: attribute it is an LDIF file!
Once you cool down you look at the file using od, just in case, and you see: