gwtupload conflict with Activities and places framework

Question

I have a GWT application which has an upload feature, and it works fine with gwtupload However, it doesn't work after I setup Activities and places framework. It gives the following submit error:

Unable to auto submit the form, it seems your browser has security issues with this feature. Developer Info: If you are using jsupload and you do not need cross-domain, try a version compiled with the standard linker?

Thanks a lot in advance!