ICY GWT Compile error

[Ben Cuthbert]

All 

I had some ant scripts and decided to integrate ivy into them. After I have 
done that I am getting compliation errors when calling
javac on the GWT code. But if I remove the ivy it all works fine. Is there any 
reference to anyone have any similar issues

I am using ivy 2.2.0-rc1

error when trying to compile is

javac_gwt:
    [javac] Compiling 255 source files to 
/Users/cuthbe/dev/code/test/war/WEB-INF/classes
    [javac] 
/Users/cuthbe/dev/code/test/src/com/test/client/event/downloader/HandlerManager.java:192:
 type parameters of <H>H cannot be determined; no unique maximal instance 
exists for type variable H with upper bounds 
H,com.test.client.event.downloader.GwtDownloadEventHander<? extends 
com.test.shared.event.GwtDownloadEvent>
    [javac]     return registry.getHandler(classType, index);