UnsupportedClassVersionError

I'm having a build failure while running Ant on a HP-UX machine. Here's the output. Everything works OK until Ant invokes the compiler. Clearly, somethign is out of synch, but I don't know where to start looking.

init:

[delete] Deleting directory /privdir/cttc999/cmWizardBuild/196251/build

[echo] Building Test Application (ecm-test.jar)

[mkdir] Created dir: /privdir/cttc999/cmWizardBuild/196251/build

[echo] os.name: HP-UX

manifest:

compile:

[javac] Compiling 1 source file to /privdir/cttc999/cmWizardBuild/196251/build

BUILD FAILED

java.lang.UnsupportedClassVersionError: com/sun/tools/javac/Main (Unsupported major.minor version 48.0)

[710 byte] By [Dick_Adamsa] at [2007-10-2 14:31:26]
# 1
JDK mismatch. Upgrade your JDK.
sahooa at 2007-7-13 12:53:43 > top of Java-index,Enterprise & Remote Computing,AVK Portability...
# 2
Mismatch between the JDK and what? I do not control the machine (a server), so have to be able to give the sysadmin specifics of what the problem is. (Would that he would do the research for me!)
Dick_Adamsa at 2007-7-13 12:53:43 > top of Java-index,Enterprise & Remote Computing,AVK Portability...