I saw a weird thing happen during an install that sounds similar to this.  It 
seems the install actually writes the dsm.opt file in the baclient directory, 
rather than copying a template file.  I have seen a corrupt file.  Edit the 
dsm.opt file and search for the CommMeth=D string that is causing the error.  
I'll bet you find it.  Just delete it.  Alternatively, copy a dsm.opt file from 
another node and update it.

Interestingly and usefully, when reinstalling the client software, the 
installation preserves the dsm.opt files from previous installations so the 
problem gets propagated.

Let me know if this works.

Kelly