Wireless not working for "thinuser" on X50C

I am testing/evaluating an X50c to use for connecting to our terminal server. Using INI file settings, I am trying to get it to connect to an open access point. It works fine if I log in as "admin" and manually connect to the network, but if I leave it to autologin as "thinuser", it never connects. I connected it with ethernet to allow it to retrieve the INI files, and confirmed that it retrieved the MAC.ini file from the FTP server.

Here's the section from my .ini file:

WLAN=GuestWireless \
SSID=guest \
Security=NONE

What am I doing wrong?