Non-ascii not allowed in data input headers

[davilima6]

This works:

"País:text" Ano Populacao feminina Populacao masculina Populacao total
Áustria 2000-01-01 59.6 77.3 68.5
Bélgica 2000-01-01 51.5 69.5 60.5

But this doesn't:

País Ano Populacao feminina Populacao masculina Populacao total
Áustria 2000-01-01 59.6 77.3 68.5
Bélgica 2000-01-01 51.5 69.5 60.5

Failing with this traceback:

Traceback (innermost last):
Module ZPublisher.Publish, line 126, in publish
Module ZPublisher.mapply, line 77, in mapply
Module ZPublisher.Publish, line 46, in call_object
Module eea.app.visualization.converter.browser, line 17, in call
Module eea.app.visualization.converter.converter, line 197, in call
Module eea.app.visualization.converter.types.guess, line 204, in call
Module eea.app.visualization.converter.types.guess, line 140, in guessBody
Module eea.app.visualization.converter.types.latitude, line 105, in call
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 2: ordinal not in range(128)