Already had an #else
The compiler detected a duplicate #else conditional compilation directive in a #if directive block. A #if directive can only have one #else directive. Ensure that you have only one #else conditional compilation directive for the #if directive in which the error occurred and compile again.
The following example illustrates this error:
public class Simple{
#if A
#if B
void method1{
//do something here
}
#else
void method2{
//do something here
#else //error: extra '#else' directive supplied
#endif
}