1) There is a problem with the way types are checked in cmDspInstInstallCb( ).
If the type was set to kTypeDsvMask (all types (as in the input to the 'printer' DSP object) 
this will include the kProxyDsvFl.

In cmDsvCanConvert() a call to _vptr() is supposed to return a pointer to the actual value
when the proxy flag is set.  This will crash because it will notice the proxy flag is
set and attempt to follow a non-existent proxy pointer. 

The cmDsvValue() system assumes that only one type flag is set.
The DSP variable 
