When I trade on a map I downloaded with a villager, at the end there is a blank trade option. I look at it, then it crashes.

When I trade on a map I downloaded with a villager, at the end of the options there is a blank trade option. I look at it, then it crashes. I am afraid to trade because I might hit the end and it might crash.
I was using a resource pack when I got this, but it still crashes without one.

Steps to Crash.
Step 1. Download a survival map with a villager shop (I used Farming Platform 4).
Step 2. Start it up.
Step 3. Go to the villager shop.
Step 4. Go to the end of their trade choices.
Step 5. Look at the empty trade.
Step 6. Crash.

Here is the Crash Report V

---- Minecraft Crash Report ----
// Who set us up the TNT?

Time: 10/30/13 5:45 PM
Description: Rendering screen

java.lang.NullPointerException: Rendering screen
	at bcd.a(SourceFile:76)
	at beb.a(SourceFile:165)
	at bll.b(SourceFile:851)
	at azd.ad(SourceFile:780)
	at azd.e(SourceFile:704)
	at net.minecraft.client.main.Main.main(SourceFile:103)


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

-- Head --
Stacktrace:
	at bcd.a(SourceFile:76)
	at beb.a(SourceFile:165)

-- Screen render details --
Details:
	Screen name: beb
	Mouse location: Scaled: (248, 72). Absolute: (497, 334)
	Screen size: Scaled: (427, 240). Absolute: (854, 480). Scale factor of 2

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bje['goldenight'/6, l='MpServer', x=-1053.11, y=8.62, z=-495.70]]
	Chunk stats: MultiplayerChunkCache: 225, 225
	Level seed: 0
	Level generator: ID 01 - flat, ver 0. Features enabled: false
	Level generator options: 
	Level spawn location: World: (-1061,4,-279), Chunk: (at 11,0,9 in -67,-18; contains blocks -1072,0,-288 to -1057,255,-273), Region: (-3,-1; contains chunks -96,-32 to -65,-1, blocks -1536,0,-512 to -1025,255,-1)
	Level time: 4304554 game time, 12079 day time
	Level dimension: 0
	Level storage version: 0x00000 - Unknown?
	Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
	Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
	Forced entities: 29 total; [rf['entity.ItemFrame.name'/7, l='MpServer', x=-1054.50, y=10.50, z=-488.06], rf['entity.ItemFrame.name'/8, l='MpServer', x=-1053.94, y=10.50, z=-487.50], rf['entity.ItemFrame.name'/9, l='MpServer', x=-1055.06, y=10.50, z=-487.50], xh['Enchanter'/10, l='MpServer', x=-1050.25, y=7.00, z=-482.50], xh['Chef'/11, l='MpServer', x=-1086.50, y=7.00, z=-549.50], xh['Hunter'/12, l='MpServer', x=-1084.50, y=7.00, z=-549.50], xh['Horseman'/13, l='MpServer', x=-1082.22, y=7.00, z=-549.53], va['Pig'/14, l='MpServer', x=-1077.84, y=7.00, z=-550.31], rf['entity.ItemFrame.name'/15, l='MpServer', x=-1083.50, y=9.50, z=-539.94], xh['Smith'/17, l='MpServer', x=-1075.22, y=7.50, z=-524.50], rf['entity.ItemFrame.name'/16, l='MpServer', x=-1073.50, y=9.50, z=-523.94], xh['Farmer'/19, l='MpServer', x=-1076.31, y=8.00, z=-490.69], xh['Lumberjack'/18, l='MpServer', x=-1083.50, y=7.50, z=-508.22], xh['Bell Ringer'/21, l='MpServer', x=-1059.88, y=23.00, z=-539.38], xh['Farmer'/20, l='MpServer', x=-1075.31, y=8.00, z=-490.31], rf['entity.ItemFrame.name'/23, l='MpServer', x=-1071.94, y=9.50, z=-511.50], rf['entity.ItemFrame.name'/22, l='MpServer', x=-1071.94, y=9.50, z=-513.50], rf['entity.ItemFrame.name'/25, l='MpServer', x=-1070.50, y=11.50, z=-500.06], rf['entity.ItemFrame.name'/24, l='MpServer', x=-1071.06, y=11.50, z=-499.50], rf['entity.ItemFrame.name'/27, l='MpServer', x=-1066.50, y=10.50, z=-508.94], rf['entity.ItemFrame.name'/26, l='MpServer', x=-1069.94, y=11.50, z=-499.50], rf['entity.ItemFrame.name'/29, l='MpServer', x=-1063.50, y=10.50, z=-496.06], rf['entity.ItemFrame.name'/28, l='MpServer', x=-1068.94, y=10.50, z=-506.50], rf['entity.ItemFrame.name'/31, l='MpServer', x=-1064.06, y=10.50, z=-495.50], xh['Bank Guard'/30, l='MpServer', x=-1071.50, y=11.00, z=-509.50], xh['Digger'/34, l='MpServer', x=-1051.50, y=7.00, z=-498.13], bje['goldenight'/6, l='MpServer', x=-1053.11, y=8.62, z=-495.70], rf['entity.ItemFrame.name'/32, l='MpServer', x=-1063.50, y=10.50, z=-494.94], xh['Priest'/33, l='MpServer', x=-1051.50, y=3.00, z=-543.50]]
	Retry entities: 0 total; []
	Server brand: vanilla
	Server type: Integrated singleplayer server
Stacktrace:
	at biz.a(SourceFile:284)
	at azd.b(SourceFile:1951)
	at azd.e(SourceFile:713)
	at net.minecraft.client.main.Main.main(SourceFile:103)

-- System Details --
Details:
	Minecraft Version: 1.7.2
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.7.0_05, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 172487112 bytes (164 MB) / 470155264 bytes (448 MB) up to 954466304 bytes (910 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G
	AABB Pool Size: 20004 (1120224 bytes; 1 MB) allocated, 3 (168 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Launched Version: 1.7.2
	LWJGL: 2.9.0
	OpenGL: Intel(R) HD Graphics GL version 3.1.0 - Build 8.15.10.2696, Intel
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Packs: [Farming Platform 4]
	Current Language: English (US)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 564 (31584 bytes; 0 MB) allocated, 48 (2688 bytes; 0 MB) used
	Anisotropic Filtering: Off (1)