[TYPO3-english] Unsupported target encoding

[Iztok Kham]

I am sorry, but I can't find a solution ...

In a new Typo3 installation (4.2.5) in the backend i get this error when 
I try to edit a page in TemplaVoila page module:

Warning: xml_parser_set_option() [function.xml-parser-set-option]: 
Unsupported target encoding "windows-1250" in /var/ww....

Can somebody please point me to the solution (BTW: I have set UTF-8 in 
install tool).

Thanks,

-- Iztok