Getting "Error in post-command-hook" with "(void-variable icicle-mode)" on switch-to-buffer after adding icicle

[KARR, DAVID]

I very recently added icicle to my Emacsen (both Cygwin Emacs 24.5.1 and 24.3.1 
on CentOS7).  Now, whenever I do "switch-to-buffer", when I press the first key 
to begin a buffer name, I see the following:

Cygwin:
        Error in post-command-hook (icomplete-post-command-hook): 
(void-variable icicle-mode)

Centos7:
        Error in post-command-hook (#[nil \301\302\303!)\207 [non-essential t 
run-hooks icomplete-post-command-hook] 2]): (void-variable icicle-mode)

I have both of these Emacs configured somewhat similarly.  What might be the 
problem here?

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