When setclasspath.bat is called on windows, it requires that the JDK be installed. Tomcat 5.5 is supposed to be compatible with the JRE since the JDT jar was included.
You probably have JAVA_HOME pointing to the JRE and JRE_HOME empty when you should have JAVA_HOME empty and JRE_HOME pointing to the JRE. PS Bugzilla is not a support forum.
*** This bug has been marked as a duplicate of 32081 ***