Trouble logging into server, me and others.

The last server I have hosted was back in 1.4.2, and it was working perfectly. I came back for 1.5.2 (one day before 1.6.1) and everyone including myself cannot connect. I have already portforwarded correctly and have done all the steps I have done before yet we keep getting "Can't reach server" and when direct connecting (to 127.0.0.1), "Bad packet id (random number, different each time)". When 1.6.1 the next day, I decided to completely reinstall minecraft. This time, the client crashed completely leaving me with this error:

---- Minecraft Crash Report ----
// I let you down. Sorry :(

Time: 7/2/13 10:30 AM
Description: Ticking screen

java.lang.NullPointerException
	at bcn.a(SourceFile:863)
	at dx.a(SourceFile:23)
	at cn.b(SourceFile:350)
	at bcn.d(SourceFile:95)
	at bcp.c(SourceFile:71)
	at atn.k(SourceFile:1172)
	at atn.S(SourceFile:662)
	at atn.d(SourceFile:618)
	at net.minecraft.client.main.Main.main(SourceFile:101)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Stacktrace:
	at bcn.a(SourceFile:863)
	at dx.a(SourceFile:23)
	at cn.b(SourceFile:350)
	at bcn.d(SourceFile:95)
	at bcp.c(SourceFile:71)

-- Affected screen --
Details:
	Screen name: bcp
Stacktrace:
	at atn.k(SourceFile:1172)
	at atn.S(SourceFile:662)
	at atn.d(SourceFile:618)
	at net.minecraft.client.main.Main.main(SourceFile:101)

-- System Details --
Details:
	Minecraft Version: 1.6.1
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.7.0_15, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 308437472 bytes (294 MB) / 344064000 bytes (328 MB) up to 954466304 bytes (910 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Launched Version: 1.6.1
	LWJGL: 2.9.0
	OpenGL: GeForce GTX 470/PCIe/SSE2 GL version 4.3.0, NVIDIA Corporation
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Pack: Default
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: ~~ERROR~~ NullPointerException: null

The server client shows no signs of anyone even trying to connect.
The 2nd attempt to connect on fresh 1.6.1, the result went back to where I started.

Note that I have already tried googling this problem, with no luck. I even taught my cousin with the same exact steps I used to make server and when he made the server, it was perfectly fine.

Downgrading to 1.4.2 and hosting my old server did not work either.

What I expected to happen was...:
The server should have worked just fine with everyone, including myself, able to connect.

What actually happened was...:
Can't reach server
Bad packet id ###
No one can connect.

Steps to Reproduce:
1. Host a 1.4.2 server
2. Quit until 1.5.2
3. Make a new server
4. Attempt to connect