Few days a go I had a PDF form that submitted the field values as a HTML POST to my CGI script. The problem was that I could fill in using English and European characters with Reader but many non-English characters was lost in the strings readed from my script. I lost the € sign and all characters above 255, but I don't lost other non-English characters like accentuated letters.
Later, I changed my form to submit the field values in a FDF file. I thought there was some kind of restriction in submit a form as HTML. Especially, because If I exported the data into a FDF file from Acrobar Professional all non-English character was preserved. But I have the same problem now. Some characters are lost in the submitted FDF file from Acrobat Reader. The English characters and some accentuated letters are preserved, but the € sign is translated to \x80 (in Windows because in Linux it is translated into \x2e). All characters above 255 are lost.