Computer in english but in eventum date is in another language

[Dr F]

Hello to all,
I got a server that was used in some eastern-european country (maybe slovakia). The server is using English language, English SO (windows server 2003). Nothing in any other language, for what i know.
I moved eventum on this server so that we can make free the computer that actually has eventum on.
I moved eventum using this procedure:
- moved the folder in C:\wamp\www\eventum to the same folder on the new server, where i also created an empty eventum DB
- deleted the content of *\config in eventum so to trig the installation
- start using eventum

Problem: on the new server everything is in english, except the dates. Every date is in slovakian or similar language (pon = mon, uto = tuesday; jàn = jan(uary) etc. ; if it wasn't because of the namedays, the months are very easy understood, almost like english but with accented letters)

I cannot understand where can be the setting of the language, and also if the problem should be in eventum or wamp.
It's possible that the first time i installed eventum the SO was in english but the regional options were in slovakian, but i think everything was in english, and anyway i re-installed eventum with ANYTHING in english and the problem was there again.
In the configuration file of eventum the language is en_US, i tried also en_GB but it works on the GUI except the dates.
Any help is welcome