Ant 1.7.1 hangs on windows

[troy . bull]

Greetings

I just installed ant on a new windows XP workstation. I have the following  
settings:

ANT_HOME=C:\bin\apache-ant-1.7.1
JAVA_HOME=C:\Java\jdk1.6.0_12

If I type
ant -version it runs, reports the version then hangs with NTVDM.exe taking  
half the cpu. Does anyone have any idea what might cause this?

Thanks
troy