I am also facing issue in Re-Generating Code after configuring the GWT-DFE setting on LR 11.52.
Performed the below.
1. Copied *.gwt.rpc files from application server to a folder GWT on LR Vugen machine.
2. Copied *.jar files into folder GWT\WEB-INF\lib (screen shot attached).
3. Copied *.classes files into folder GWT\WEB-INF\classes
4. Created class path for these files in Recording Options>>DFE>>Chain Configuration.
5. Followed the steps in video http://www.youtube.com/watch?v=ASD8xj0otUk
6. Also replaced the <LoadRunner>\jre directory with <Program Files>\Java\jre6 before recording a GWT Application.
Yet on regeneration getting 'Failed to create web_convert_from_formatted step. Decoded data is empty or has invalid tags.'