Peter,
Concerning your first question,Labview V6.1 does not offer more Differential Equation routines than V6.0.
For the second question, I don't know if there are such libraies available. Perhaps somebody on the forum will be able to help you out. I've been looking around and didn't find anything except for a white paper that shows programming PDE in the G environment.
http://www.imamod.ru/jour/conf/IMACS_2000/CP/518-3.pdf
Might interest you.
Regards,
Cyril Bouton
Applications Engineer
National Instruments
Cyril Bouton
Active LabVIEW Developper