Settings work in Simulator but not on iOS device

Hi Everyone, I have a root.plist bundle setting (in platform.iphone.Settings.bundle) that works perfectly fine in the simulator but only yields a blank settings screen on an iPod touch under iOS4. In other words, the settings have an entry for my app, but when I select it I only get a blank window. Anybody have an idea what's wrong with this:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>PreferenceSpecifiers</key>
    <array>
        <dict>
            <key>Type</key>
            <string>PSGroupSpecifier</string>
            <key>Title</key>
            <string>User Interface</string>
        </dict>
        <dict>
            <key>Type</key>
            <string>PSMultiValueSpecifier</string>
            <key>Title</key>
            <string>Color Scheme</string>
            <key>Key</key>
            <string>col_pref</string>
            <key>DefaultValue</key>
            <string>Dark</string>
            <key>Values</key>
            <array>
                <string>Dark</string>
                <string>Light</string>
            </array>
            <key>Titles</key>
            <array>
                <string>Dark</string>
                <string>Light</string>
            </array>
        </dict>
        <dict>
            <key>Type</key>
            <string>PSGroupSpecifier</string>
            <key>Title</key>
            <string>Quick Facts Display Options</string>
        </dict>
        <dict>
            <key>Type</key>
            <string>PSMultiValueSpecifier</string>
            <key>Title</key>
            <string>Temperature Unit</string>
            <key>Key</key>
            <string>temp_pref</string>
            <key>DefaultValue</key>
            <string>Fahrenheit</string>
            <key>Values</key>
            <array>
                <string>Celsius</string>
                <string>Fahrenheit</string>
            </array>
            <key>Titles</key>
            <array>
                <string>Celsius</string>
                <string>Fahrenheit</string>
            </array>
        </dict>
    </array>
</dict>
</plist>