Hi,
Until I can figure out what the problem is, you can use the /Applications/Dynare/4.3.0/matlab/dynare_m file. That way, you can still use some of the non-preprocessor bug fixes that were created in the 4.3.1 release (i.e. not ifdef, ifndef, and ohters....see:
http://www.dynare.org/DynareWiki/KnownBugs )
The other option is to upgrade to 10.8.
When I fix this, I'll make a post here (hopefully in the next few days).