It is an encrypted virus. It contains two macros: AutoOpen, DateiSpeichernUnter and infects global macros area on opening an infected file, and writes itself to documents on saving them with new name (FileSaveAs).
If day number >= 15th and month number >= 7 (July) the virus displays the message box with the text:
Happy Birthday
Herzlichen Glückwunsch
Susanne B. aus E.
zu deinem Geburtstag
Ich liebe dich
