Read output of shell command to a buffer fails

[Hal]

Using Vim 7 on OS X, my command line use of shell commands works  
properly, but when I use ':r !<cmd>' to read the output of a shell  
command into a file, I consistently get the following error.

/bin/bash error on line 1
shell returned 1
E485 Can't read file /tmp/........
I'm pretty sure I've had this work on prior uses of Vim and am  
guessing a setting is wrong, but I don't know which.  Any suggestions?

TIA,  Hal