I am not sure if the cascade vanes had anything to do with it. As mentioned earlier, the damage was to the inner region of the "D" duct, as shown by these photos on the following discussion thread;
http://www.airliners.net/discussions...d.main/172795/
The cascade vanes are located under the translating TR sleeve on the outer part of the "D" duct. Further photos appear on the following discussion thread;
http://www.airliners.net/discussions....main/3082811/