LyX dumps core with locale setting at UTF-8

[Marco Beishuizen]

Hi,

My LyX (1.6.8) is exiting with:
...
terminate called after throwing an instance of 'std::runtime_error'
  what():  locale::facet::_S_create_c_locale name not valid
Abort (core dumped)
...
It seems a problem with the locale setting. When using en_US.UTF-8, LyX 
aborts like above. When setting locale to "C", it runs without problems. 
But I want to use UTF-8 for accents etc. so how can I let LyX run with 
UTF-8?

I'm using LyX on FreeBSD 8.1-STABLE.

Thanks in advance,
Marco

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