The templates for wxFormbuilder are in
share/CodeBlocks/templates/wizard/wxwidgets/wxfb
You can overwrite them with the new format files, but the problem is here:
[New files] cannot be compiled in code::blocks any longer
You must investigate why the files generated by wxFormBuilder are not compilable, and then file a bug where applicable. You can post a full rebuild log in code tags here (words in bold are important).