I recently installed SCIRun on my new MacBook Pro using the latest svn build.  It turns out that this version (v1.25.3) no longer uses *.net networks, rather saves new networks as *.srn.  Although it can open older *.net networks, what are the main differences between the two extensions?

Also, when opening simple surfaces that we've created in previous versions as fields (using FieldReader), I get the following error in ShowField (when I try to display the surfaces):

ERROR: Module crashed with the following exception:

  An AssertionFailed exception was thrown from file:

  ../src/Core/Geometry/BBox.cc:172

  is_valid

ERROR: Thread Stacktrace:

ERROR: 

Any ideas how to fix this?  Or at least be able to convert our older fields into a format that the newest build of SCIRun can use?  Thanks in advance for your help!