[Typo3] Unsupported target encoding "windows-1250"

[Vlatko Surlan]

Hi all. Could you please tell me why am I getting this error message:
"Warning: xml_parser_set_option() [function.xml-parser-set-option]: 
Unsupported target encoding "windows-1250" in 
/home/stop1/public_html/typo3_src-3.8.0/t3lib/class.t3lib_div.php on 
line 1907"

It appears in the backend above the content cell. This started after 
I've set force-charset to windows-1250.