I've changed from CARM to Realview too. I'm facing the same problem with LPC2129. Following the Data abort analisys the problem is in the __SWI_2 subroutine in the ar_lib.o (I don't have the source code of ARTX).
Sorry, you have analysed it already. I did not carefully read your post.
Is the stack locate in a correct address space? What is the instruction that causes the data abort and what is the register contect at this time?