[TYPO3-seminars] Problem with localization

[Rolf Thiele]

Hi everyone,
I'm struggling with a strange localization issue.

For some reason, my confirmation mails look like this:
"Sehr geehrter Herr Test,

Guten Tag Beispielkursname,

vielen Dank für Ihre Anmeldung zu dieser Veranstaltung: am 08.05.2010  
von 08:00 bis 15:00 Uhr at the total price of € 20,00."

Also, in the BE, tx_seminars_seminars.cancelled is not localized, the  
values in the drop down field are shown in English.

I have several websites using seminars, and only one of them  
encounters these problems. So I tried to copy the seminars folders in  
typo3conf/ l10n and in typo3conf/ext from another website, but that  
didn't solve the problems. Also uninstalling and reinstalling seminars  
didn't work.

Does anyone habe any idea what I could do to solve this problem?

TYPO3 4.2.12
seminars 0.9.0
oelib 0.7.1

Thanks,
Rolf