Can't register my copy of Zend Studio

[avaranger]

When I try to regster my Zend Studio, it results in an error saying "Error writing serial number" (my license is valid - http://snag.gy/FHuiD.jpg). Any ideas where does it write the information?

I use Windows 8. This appeared after I changed my username from one having diacritics (problems with nearly everything linux-based - git, sh, etc.) to asci one. Where does ZS save this info?