Crash when joining Multiplayer game

---- Minecraft Crash Report ----
// Why is it breaking :(

Time: 2014-05-25 20:19
Description: Rendering screen

java.lang.IllegalArgumentException: bad Base64 input character at 4907: 0 (decimal)
	at io.netty.handler.codec.base64.Base64.decode(Base64.java:247)
	at io.netty.handler.codec.base64.Base64.decode(Base64.java:197)
	at io.netty.handler.codec.base64.Base64.decode(Base64.java:188)
	at bhc.b(SourceFile:155)
	at bhc.a(SourceFile:130)
	at bbd.a(SourceFile:26)
	at bbi.b(SourceFile:382)
	at bbi.a(SourceFile:259)
	at bgz.a(SourceFile:283)
	at bms.b(SourceFile:852)
	at azl.ah(SourceFile:784)
	at azl.f(SourceFile:711)
	at net.minecraft.client.main.Main.main(SourceFile:148)


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

-- Head --
Stacktrace:
	at io.netty.handler.codec.base64.Base64.decode(Base64.java:247)
	at io.netty.handler.codec.base64.Base64.decode(Base64.java:197)
	at io.netty.handler.codec.base64.Base64.decode(Base64.java:188)
	at bhc.b(SourceFile:155)
	at bhc.a(SourceFile:130)
	at bbd.a(SourceFile:26)
	at bbi.b(SourceFile:382)
	at bbi.a(SourceFile:259)
	at bgz.a(SourceFile:283)

-- Screen render details --
Details:
	Screen name: bgz
	Mouse location: Scaled: (217, 167). Absolute: (653, 521)
	Screen size: Scaled: (427, 342). Absolute: (1280, 1024). Scale factor of 3
Stacktrace:
	at bms.b(SourceFile:852)
	at azl.ah(SourceFile:784)
	at azl.f(SourceFile:711)
	at net.minecraft.client.main.Main.main(SourceFile:148)

-- System Details --
Details:
	Minecraft Version: 1.7.5
	Operating System: Windows XP (x86) version 5.1
	Java Version: 1.7.0_55, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
	Memory: 31002584 bytes (29 MB) / 69885952 bytes (66 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Launched Version: 1.7.5
	LWJGL: 2.9.1
	OpenGL: Intel Bear Lake B GL version 1.4.0 - Build 7.15.10.4969, Intel
	GL Caps: Using GL 1.3 multitexturing.
Not using framebuffer objects because OpenGL 1.4 is supported, EXT_blend_func_separate is supported, OpenGL 3.0 is not supported, ARB_framebuffer_object is not supported, and EXT_framebuffer_object is not supported.
Anisotropic filtering is supported and maximum anisotropy is 4.
Shaders are not available because OpenGL 2.1 is not supported, ARB_shader_objects is not supported, ARB_vertex_shader is not supported, and ARB_fragment_shader is not supported.

	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Packs: []
	Current Language: Svenska (Sverige)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Anisotropic Filtering: Off (1)