Hi,
For what it is worth, I had the same problem and following the advice of Kiran and Christiano I put the SWCV in and out of edit mode a couple if times and eventually was able to create the initial namespace. I found that after creating the first namespace I had no more problems. Also note that I could not find any entry in any log related to this issue - the default trace as such does not appear to available 7.3 any more and is replaced by the more generic sap logs.
Stephen