md5 hashing acting strangly?

[Sean Campbell via Digitalmars-d-learn]

i have the following code
char[] Etag(string file){
        auto info = DirEntry(file);
        ubyte[16] hash = md5Of(to!string(info.timeLastAccessed.day)~
                               to!string(info.timeLastAccessed.month)~
                               to!string(~info.timeLastAccessed.year)~
                               file);
        char[] hashstring = toHexString(hash);
        writeln(hashstring);
        return hashstring;
}
the proper hash string prints out in the console, but when i try 
to use the return value of Etag it becomes an obscure string?