What does this mean?

Minecraft has crashed!     
      ----------------------     

Minecraft has stopped running because it encountered a problem; Updating screen events

A full error report has been saved to C:\Users\Admin\AppData\Roaming\.minecraft\crash-reports\crash-2013-04-03_13.31.43-client.txt - Please include a copy of that file (Not this screen!) if you report this crash to anyone; without it, they will not be able to help fix the crash :(

--- BEGIN ERROR REPORT ecad23d6 --------
Full report at:
C:\Users\Admin\AppData\Roaming\.minecraft\crash-reports\crash-2013-04-03_13.31.43-client.txt
Please show that file to Mojang, NOT just this screen!

Generated 4/3/13 1:31 PM

-- Head --
Stacktrace:
 at java.lang.Thread.start0(Native Method)
 at java.lang.Thread.start(Unknown Source)
 at ci.d(SourceFile:371)
 at bdl.b(NetClientHandler.java:649)
 at bdt.D(SourceFile:194)
 at axl.a(SourceFile:46)
 at axr.a(SourceFile:72)
 at axr.d(SourceFile:127)
 at axr.m(SourceFile:111)

-- Affected screen --
Details:
 Screen name: axl

-- Affected level --
Details:
 Level name: MpServer
 All players: 1 total; [bdw['iUsEdApIcK'/4730195, l='MpServer', x=-446.14, y=66.62, z=1615.87]]
 Chunk stats: MultiplayerChunkCache: 289
 Level seed: 0
 Level generator: ID 00 - default, ver 1. Features enabled: false
 Level generator options:
 Level spawn location: World: (841,65,-3296), Chunk: (at 9,4,0 in 52,-206; contains blocks 832,0,-3296 to 847,255,-3281), Region: (1,-7; contains chunks 32,-224 to 63,-193, blocks 512,0,-3584 to 1023,255,-3073)
 Level time: 18880285 game time, 20048043 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: 17 total; [ru['Creeper'/4730424, l='MpServer', x=-475.50, y=22.00, z=1643.50], rj['entity.MinecartChest.name'/4730216, l='MpServer', x=-466.53, y=41.34, z=1649.19], qr['Squid'/4730210, l='MpServer', x=-492.50, y=60.28, z=1621.19], qg['Bat'/4730215, l='MpServer', x=-483.49, y=13.08, z=1653.51], rj['entity.MinecartChest.name'/4730214, l='MpServer', x=-385.50, y=47.50, z=1619.50], sf['Skeleton'/4730200, l='MpServer', x=-472.72, y=18.00, z=1592.78], sh['Spider'/4730201, l='MpServer', x=-416.16, y=64.00, z=1639.38], rv['Enderman'/4730202, l='MpServer', x=-467.22, y=19.00, z=1637.88], qg['Bat'/4730203, l='MpServer', x=-473.16, y=17.39, z=1648.75], rj['entity.MinecartChest.name'/4730204, l='MpServer', x=-413.50, y=41.50, z=1583.50], qr['Squid'/4730205, l='MpServer', x=-487.06, y=59.31, z=1608.50], rj['entity.MinecartChest.name'/4730206, l='MpServer', x=-436.50, y=45.50, z=1654.50], qi['Chicken'/4730196, l='MpServer', x=-433.78, y=63.00, z=1592.53], rh['item.item.egg'/4730197, l='MpServer', x=-433.75, y=63.13, z=1592.38], sf['Skeleton'/4730198, l='MpServer', x=-436.42, y=35.00, z=1593.99], ru['Creeper'/4730199, l='MpServer', x=-463.34, y=39.00, z=1646.69], bdw['iUsEdApIcK'/4730195, l='MpServer', x=-446.14, y=66.62, z=1615.87]]
 Retry entities: 0 total; []
Stacktrace:
 at bdt.a(SourceFile:282)
 at net.minecraft.client.Minecraft.b(SourceFile:1881)
 at net.minecraft.client.Minecraft.run(SourceFile:535)
 at java.lang.Thread.run(Unknown Source)

-- System Details --
Details:
 Minecraft Version: 1.5.1
 Operating System: Windows 7 (x86) version 6.1
 Java Version: 1.7.0_13, Oracle Corporation
 Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
 Memory: 394205440 bytes (375 MB) / 519110656 bytes (495 MB) up to 1037959168 bytes (989 MB)
 JVM Flags: 2 total; -Xms512m -Xmx1024m
 AABB Pool Size: 1668 (93408 bytes; 0 MB) allocated, 2 (112 bytes; 0 MB) used
 Suspicious classes: IWrUpdater, Config, WrUpdates, ...[reifnsk.minimap.ReiMinimap, GuiScreenInterface, GuiOptionScreen, ...]
 IntCache: cache: 0, tcache: 6, allocated: 3, tallocated: 63
 ModLoader: Mods loaded: 2
ModLoader 1.5.1
mod_ReiMinimap v3.3_04 [1.5.1]

 LWJGL: 2.4.2
 OpenGL: GeForce 9400 GT/PCI/SSE2 GL version 3.3.0, NVIDIA Corporation
 Is Modded: Very likely; Jar signature invalidated
 Type: Client (map_client.txt)
 Texture Pack: Default
 Profiler Position: N/A (disabled)
 Vec3 Pool Size: 1621 (90776 bytes; 0 MB) allocated, 14 (784 bytes; 0 MB) used

java.lang.OutOfMemoryError: unable to create new native thread
 at java.lang.Thread.start0(Native Method)
 at java.lang.Thread.start(Unknown Source)
 at ci.d(SourceFile:371)
 at bdl.b(NetClientHandler.java:649)
 at bdt.D(SourceFile:194)
 at axl.a(SourceFile:46)
 at axr.a(SourceFile:72)
 at axr.d(SourceFile:127)
 at axr.m(SourceFile:111)
 at net.minecraft.client.Minecraft.l(SourceFile:1078)
 at net.minecraft.client.Minecraft.K(SourceFile:574)
 at net.minecraft.client.Minecraft.run(SourceFile:526)
 at java.lang.Thread.run(Unknown Source)
--- END ERROR REPORT 5888a356 ----------