[Koha] Copies available… but only if the OPAC language is English

[Mirko]

Dear list,

as stated in the subject: when I search in the OPAC, in the results
page I get "Availability: Copies available for loan:" etc. -- but
only if the OPAC language is English. If it's German, Turkish,
Spanish, Polish or Russian, I get "No copies available" (in the
resp. language) [if it's French i get "Erreur 500"].

Is that a known problem? Does it work as it should for others? Did I
do something wrong with the translation files? (I do not really
remember how i installed them, I had to do it manually I think).
I'm on Koha 3.2.5 using the Debian-packages on Squeeze,
OPACXSLTResultsDisplay is on.

Any help is appreciated,

Mirko