In fact, I was able to reproduce the problem with a simple test idl file.
Here is the idl foo.idl:
------------------------------------------------------------------------------
module foo {
  struct TnhsAlarmOperations {
    long junk;
  };
};
------------------------------------------------------------------------------

This Attachment shows a stackTrack that I dumped in a modified version of
lexer.java - with debug output in strictJavaEscapeCheck.

     [java] strictJavaEscapeCheck found String TnhsAlarmOperations needs escape
     [java] Dumping the stack to see who calls this:
     [java] java.lang.NullPointerException
     [java] 	at org.jacorb.idl.lexer.strictJavaEscapeCheck(Unknown Source)
     [java] 	at org.jacorb.idl.IdlSymbol.escapeName(Unknown Source)
     [java] 	at org.jacorb.idl.StructType.parse(Unknown Source)
     [java] 	at org.jacorb.idl.TypeDeclaration.parse(Unknown Source)
     [java] 	at org.jacorb.idl.Definition.parse(Unknown Source)
     [java] 	at org.jacorb.idl.SymbolList.parse(Unknown Source)
     [java] 	at org.jacorb.idl.Module.parse(Unknown Source)
     [java] 	at org.jacorb.idl.Definition.parse(Unknown Source)
     [java] 	at org.jacorb.idl.Spec.parse(Unknown Source)
     [java] 	at org.jacorb.idl.CUP$actions.CUP$do_action(Unknown Source)
     [java] 	at org.jacorb.idl.parser.do_action(Unknown Source)
     [java] 	at java_cup.runtime.lr_parser.parse(Unknown Source)
     [java] 	at org.jacorb.idl.parser.compile(Unknown Source)
     [java] 	at org.jacorb.idl.parser.compileAndHandle(Unknown Source)
     [java] 	at org.jacorb.idl.parser.main(Unknown Source)
------------------------------------------------------------------------------
*** So, the question is, why is it doing this for a STRUCTURE whose name
CONTAINS one of the 6 restricted keywords, but is not equal to
one of the 6 restricted keywords?