Dear friend,
To run one or more Bc's, in Nastran, use spcadd card for n number of the Bc's and specify loadsteps for each subcases. i.e., for each and every Bc's specify subcases.
I think if you try to do the above mentioned point, u will get the result.
kumaravel.
Dear gisky,
for more resources about the non-linear parameter like study, you can search all kinds of search engines.
And, my suggestion for Meshing, Hypermesh, Ansa, Medina are the powerful tool. Among this Hypermesh, is the tool which does tetra,hexa/penta,shell, all kinds of meshing..