Theos tweak: helloworld alert box did not show up - jailbreak

Question

I followed http://brandontreb.com/beginning-jailbroken-ios-development-building-and-deployment
to make a tweak. every thing seems fine and make package install is successfull,
but when my iPhone respring, the "helloworld" box did not show up,
done any one knows how to solve this?
my xcode is 4.6 and sdk5.1 is installed
my iPhone is iOS6.1.2
I set those
export THEOS=/opt/theos/
export SDKVERSION=5.1
export THEOS_DEVICE_IP=192.168.1.101
this is Makefile
export ARCHS=armv7
export TARGET=iphone:5.1
include $(THEOS)/makefiles/common.mk
helloworld_FRAMEWORKS = UIKit
TWEAK_NAME = helloworld
helloworld_FILES = Tweak.xm
include $(THEOS)/makefiles/tweak.mk
and this is Tweak.xm
#import <SpringBoard/SpringBoard.h>
%hook SpringBoard
-(void)applicationDidFinishLaunching:(id)application {
%orig;
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Welcome"
message:#"Hello world"
delegate:nil
cancelButtonTitle:#"123"
otherButtonTitles:nil];
[alert show];
[alert release];
}
%end

Answer 1

I figure it out, the *.plist should be
{ Filter = { Bundles = ( "com.apple.springboard" ); }; }
thanks #H2CO3, i find your comment somewhere else
but after i done successfully with the helloworld tweak.
I hook the fopen using MSHookFunction
and then i meet a linking error
Making all for tweak hw...
Preprocessing Tweak.xm...
Compiling Tweak.xm...
Linking tweak hw...
Undefined symbols for architecture armv7:
"_MSHookFunction", referenced from:
global constructors keyed to Tweak.xm.mmin Tweak.xm.51941273.o
ld: symbol(s) not found for architecture armv7
collect2: ld returned 1 exit status
make[2]: *** [.theos/obj/hw.dylib.ba964c90.unsigned] Error 1
make[1]: *** [internal-library-all_] Error 2
make: *** [hw.all.tweak.variables] Error 2
this is Tweak.xm
#import "substrate.h"
static FILE * (*s_orig_fopen) ( const char * filename, const char * mode );
static FILE * my_fopen ( const char * filename, const char * mode ){
return s_orig_fopen(filename, mode);
}
static void entry(void) __attribute__ ((constructor));
static void entry(void) {
MSHookFunction(fopen, my_fopen, &s_orig_fopen);
}