I am using hudson 1.323 and clearcase plugin 1.0.2
My projects use clearcase UCM and the build scripts need the 2 variables
CLEARCASE_VIEWNAME and CLEARCASE_VIEWPATH
These 2 variables are often resolved but sometimes they are not resolved. Let's
say 1/10 (once it's not resolved , 9 times it's fine).
For instance log error when I want to use an ant script specifying a build.xml
FATAL: Unable to find build script at
/app/PROJECT/build/IC/HUDSON_HOME/jobs/INT-build-UI/workspace/${CLEARCASE_VIEWNAME}/vobs/kormo_ui/ui/misc/build.xml
This is really annoying since we are using the continuous integration game
plugin , and dev are not happy to loose points when the build fails because
these 2 variables are not resolved 
For few critical projects , I decided to harcode the clearcase viewname to avoid
this situation but I would prefer not hardcode it
Im guessing that you are running an Ant task BEFORE anything else? The reason
for the change is that we wanted to fix issue 2606 and therefore "removed" the
caching of the viewname that was evaluated only once. Since slaves then would
have the wrong viewname it broke the builds on the slaves.
Not exactly sure how to fix this problem without breaking slave builds again.
If the batch task is running AFTER a checkout for example it should work.