Is your official parts library up-to-date?
55704 has been in the official library since update 2012-01
973pb0 has been in the official library since update 2011-02
98722 is still unofficial - see here, but note that you'll also have to install its subpart (98722s01) in the parts/s/ folder. Please remember that unofficial parts may be incomplete, or inaccurate, and it is possible that when they are officially released they may be changed in ways that could mess up any model you use them in.
55704 has been in the official library since update 2012-01
973pb0 has been in the official library since update 2011-02
98722 is still unofficial - see here, but note that you'll also have to install its subpart (98722s01) in the parts/s/ folder. Please remember that unofficial parts may be incomplete, or inaccurate, and it is possible that when they are officially released they may be changed in ways that could mess up any model you use them in.
Chris (LDraw Parts Library Admin)