Error using makejson

[rhoenerSBS]

I get the following error when trying to use the makejson command:
"make-json - Error: Error: Invalid PO file format: expected 'msgid ""' at the start of the header"

The PO-files in question are created from pot files that were generated using your make-pot command. The pot files get a Copyright and License information before the msgid during generation. So either the copyright information should be put at a different spot or the makejson command should be able to handle them without breaking.