In 4.0 they use android: prefix for styles but in 2.2 they does not recognise
In 4.0
<?xml version="1.0" encoding="utf-8"?>
<resources>
<style name="CodeFont" parent="@android:style/TextAppearance.Medium">
<item name="android:layout_width">fill_parent</item>
<item name="android:layout_height">wrap_content</item>
<item name="android:textColor">#00FF00</item>
<item name="android:typeface">monospace</item>
</style>
</resources>
in 2.2
<style name="WindowTitle">
<item name="singleLine">true</item>
<item name="textAppearance">@style/TextAppearance.WindowTitle</item>
<item name="shadowColor">#BB000000</item>
<item name="shadowRadius">2.75</item>
</style>
like wise things changed. So refer the android developer.android.com
Or you can use separate stylesheet from 2.2 . And also without seen the style.xml we cant say that this is the exact problem.