[Scribus]scribus.pot file - Translation

[Revuo]

I'm not an expert.
I'm using Kbabel to translate.
The system of translations was modified. Now it has a prefix telling where the 
msgid is used. Does people have to copy it too into msgstr? Translated?
Is it possible to merge the old .po file into the new one?
During this operation I received this error maybe due to the prefixes not in 
the previous po file.

>>>>
[revuo at localhost 1.1.1]$ msgmerge ../scribus.it.po scribus-1.1.1.pot > 
scribus.it.po
scribus-1.1.1.pot:1583: definizione del messaggio duplicata
scribus-1.1.1.pot:1580: ...questa ? la posizione della prima definizione
msgmerge: found 1 fatal error
<<<<

With the prefixes many translations don't appear in the side window because 
the similarity is not a lot. Is it normal or there is a system to make them 
appear?

Thanks,
Pier Luigi Cinquantini