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?