Murat,
One idea for non-English language is that all the localization files or configuration files (*.ini) or any edited files were saved in encoding type: Unicode. If you are using Notepad to save your changes, when you press save or save as there is an Encoding type selection next to the "Save" button. Make sure it is Unicode (not Aschii).
Here is the definition of Unicode Wiki: http://en.wikipedia.org/wiki/Unicode
If you look at the Wiki Unicode characters support Non-English or character type better.
The above is just a trick we use in support. Also when Agentry implemented multilingual support the code supported Unicode encoding.
This is one idea.
Another idea is to dive in the log files just before the failure occurred for Replacing Definition for EditFieldStyle. Check which file it used. Try opening it in Notepad and click Save As - See what encoding it is using (The Encoding will be displayed next to the Save button).
Regards,
Mark Pe
SAP Senior Support Engineer (Mobility)