exception expanding war file

Task is expanding a war file.  this has worked for all of my tests but not working at customer site.  the OS is Windows Server 2008 R2. the exception is:
BUILD FAILED
file:S:/xxxxx/xxxxxx/nftempdir/servletswar.xml:5: 
Error while expanding S:\xxxxx\xxxxx\webapps\theservlets.war
        at 
org.apache.tools.ant.taskdefs.Expand.expandFile(Expand.java:164)
        at 
org.apache.tools.ant.taskdefs.Expand.execute(Expand.java:127)
        at 
org.apache.tools.ant.Task.perform(Task.java:341)
        at 
org.apache.tools.ant.Target.execute(Target.java:309)
        at 
org.apache.tools.ant.Target.performTasks(Target.java:336)
        at 
org.apache.tools.ant.Project.executeTarget(Project.java:1339)
        at 
org.apache.tools.ant.Project.executeTargets(Project.java:1255)
        at 
org.apache.tools.ant.Main.runBuild(Main.java:609)
        at 
org.apache.tools.ant.Main.start(Main.java:196)
        at 
org.apache.tools.ant.Main.main(Main.java:235)
Caused by: 
java.util.zip.ZipException: invalid stored block lengths
        at 
java.util.zip.InflaterInputStream.read(Unknown Source)
        at 
java.util.zip.ZipInputStream.read(Unknown Source)
        at 
java.io.FilterInputStream.read(Unknown Source)
        at 
org.apache.tools.ant.taskdefs.Expand.extractFile(Expand.java:247)
        at 
org.apache.tools.ant.taskdefs.Expand.expandFile(Expand.java:157)
        ... 9 more

What could cause this?  I thought maybe the zip/unzip program(s) installed on platform or something.  I doubt it is related at all specifically to ant or java.  any thoughts?

thanks
KM