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).
Please analyze the reason for the data abort as described in: http://www.keil.com/support/docs/3080.htm
Does the problem exist with one of the examples that we are providing in the folder C:\Keil\ARM\RV30\RTL\Kernel\Examples.
Did you try the simplest example C:\Keil\ARM\RV30\RTL\Kernel\Examples\RTX_ex1 (note that you should select the Eval Board that you want to use).
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?