It’s because continue is a reserved symbol in Java, so you cannot use it as a name for any object in your XML files or Java code.
The reason this is a problem is that the XML defined in your project is translated into Java code that the Dalvik VM can understand. So, your code above translates into the following in R.java:
public final class R {
public static final class string {
public static final int continue=0x7f040000;
}
}
The problem is more obvious when examining the (would-be) generated code.
See list of reserved Java symbols for others to avoid.