Translating marketpress to Dutch language

Whenever i try to translate marketpress with poedit and save it this error message comes up:

Sat Feb 22 14:05:43 2014: /var/folders/fd/63_l96v12vz7xpqp8nq5khfr0000gn/T/poeditpRgyhm/0ref.pot:6500: dubbele definitie van een bericht...
Sat Feb 22 14:05:43 2014: /var/folders/fd/63_l96v12vz7xpqp8nq5khfr0000gn/T/poeditpRgyhm/0ref.pot:2768: ...dit is de plek van de eerste definitie
Sat Feb 22 14:05:43 2014: /Applications/Poedit.app/Contents/PlugIns/GettextTools.bundle/Contents/MacOS/bin/msgmerge: 1 fatale fout gevonden

It say's double definition of a message, and 1 fatale error found. What could this be ?