Hi Thomas,

there problem is related to all languages that are defined as synonyms
for other languages, this means the same happens for uk and us.

I found a solution by changing the definition from \defaultlanguage in lang-ini.tex.
Add the next macro to your document.

\def\defaultlanguage#1%
  {\ifcsname\??la#1\c!default\endcsname
     #1%
   \else
     \csname\??la#1\c!default\endcsname
   \fi}

Wolfgang