ERROR: Replacing a fix, but new style != old style

Hello,
Attached is the input file I am trying to run. I get "ERROR: Replacing a fix, but new style != old style", which is due to the heat fix part of the file. However, I don't understand why the heat fix part is causing a problem. That is, I don't understand what "new style != old style" means and how to fix that. Any ideas?
Thanks,
Annie