3.1.2: What's going on here?

[stephen.talley@xxxxxxxxxxxxxxx (Steve Talley)]

I've just compiled zsh 3.1.2 for Solaris 2.5.1 on sparc and i386.  It
seems to run fine, but I constantly get the error "zsh: not an
identifier".  Example:

 5 % echo $USERNAME
zsh: not an identifier: $USERNAME
 5 % echo $ZSH_VERSION 
zsh: not an identifier: $ZSH_VERSION
 5 % cd /tmp
zsh: not an identifier: /tmp
 5 % ls /etc
zsh: not an identifier: /etc
 5 % echo hello
hello
 6 % cd tmp

What's going on here?  The last two statements do work.

Any help is appreciated,

Steve