It looks like the problem lies with using the $n variables, which probably changes the utf-8 flag for them: if you move the user => ucfirst(lc($3)).uc(substr($4,0,1)) line above the ones where you create lname and fname then the user field is created properly but lname isn't.

The problem also exists in perl 5.6.1 but it is fixed in perl 5.8.0. You should probably use 5.8.0 if you want to work with Unicode characters anyway: unicode regexps and hash keys are only documented as working starting with this version.