[leonard]

I have this problem

Code:

[javac] Compiling 1178 source files to C:\exj\classes
[javac] java.lang.NoClassDefFoundError: com/sun/tools/javac/Main
[javac] Exception in thread "main"

BUILD FAILED

C:\dbC\build.xml:75: Compile failed, messages should have been provided.

Total time: 1 second

what's the problem?
do you have any ideas?
thanks