Usually, this is due to a space in the WDIR path line
C:\WDIR; C:\AATK_1234
You can check this out by downloading my favorite shareware RAPIDEE. WWW RAPIDEE COM
RapidEE takes the hassle out of working with environment variables. To change System variables, you have to right click and run as Administrator.
If all else fails try a reboot.
You can also see from the above example, in VX the traditional WDIR has a new env var for each release and you will need to set each one up with the AATK path.
-kendall