Fixed Windows build.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@58186 65644016-39b1-43b1-bf79-96bc8fe82c15
Protection against the not supported mode. I used a non-translatable error because it might be a temporary measure, time will show.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@58187 65644016-39b1-43b1-bf79-96bc8fe82c15