In specific conditions the parser will fail when an environment variable is the first element of an expression.

Originally reported by John_c here: http://www.kixtart.org/ubbthreads/showfl...;gonew=1#UNREAD

This code:
Code:
"Version: " @KIX ?
"1 " "%WINDIR%" ?
"2 " (%WINDIR%) ?
"3 " CStr(%WINDIR%) ?
"4 " ""+%WINDIR% ?
"5 " %WINDIR% ?


Produces:
Code:
C:\Temp>kix32 err.kix
Version: 4.50
1 C:\Windows
2 C:\Windows
3 C:\Windows
4 C:\Windows
5
ERROR : unknown command [%WINDIR%]!
Script: C:\Temp\err.kix
Line  : 6


It may also fail when the environment variable is the first part of an expression, such as:
Code:
%WINDIR%+"" ?