I tried to place different logs by command
/setblock ~ ~ ~ minecraft:log 0
/setblock ~ ~ ~ minecraft:log 1
etc.
I noticed there's no acacia log between 1 and 15, so i took acacia log from creative inventory and tried to place it manually. Than hug happens:

---- Minecraft Crash Report ----
// Don't be sad, have a hug! <3

Time: 18.06.14 19:44
Description: Unexpected error

java.lang.IllegalArgumentException: Cannot set property ayi

as it does not exist!
at axy.a(SourceFile:128)
at atx.a(SourceFile:35)
at afg.a(SourceFile:61)
at aht.a(SourceFile:113)
at bxx.a(SourceFile:313)
at blh.ar(SourceFile:1320)
at blh.q(SourceFile:1677)
at blh.ap(SourceFile:860)
at blh.a(SourceFile:303)
at net.minecraft.client.main.Main.main(SourceFile:121)

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

– Head –
Stacktrace:
at axy.a(SourceFile:128)
at atx.a(SourceFile:35)
at afg.a(SourceFile:61)
at aht.a(SourceFile:113)
at bxx.a(SourceFile:313)
at blh.ar(SourceFile:1320)

– Affected level –
Details:
Level name: MpServer
All players: 1 total; [cbw['Toboe_Irbis'/59, l='MpServer', x=635,24, y=85,12, z=20,41]]
Chunk stats: MultiplayerChunkCache: 365, 365
Level seed: 0
Level generator: ID 00 - default, ver 1. Features enabled: false
Level generator options:
Level spawn location: 531,00,56,00,185,00 - World: (531,56,185), Chunk: (at 3,3,9 in 33,11; contains blocks 528,0,176 to 543,255,191), Region: (1,0; contains chunks 32,0 to 63,31, blocks 512,0,0 to 1023,255,511)
Level time: 92014 game time, 6827 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: creative (ID 1). Hardcore: false. Cheats: false
Forced entities: 28 total; [yz['Sheep'/67, l='MpServer', x=661,50, y=71,76, z=-23,50], cbw['Toboe_Irbis'/59, l='MpServer', x=635,24, y=85,12, z=20,41], zc['Squid'/10, l='MpServer', x=594,19, y=49,34, z=57,50], yn['Bat'/11, l='MpServer', x=598,33, y=33,02, z=65,08], zc['Squid'/13, l='MpServer', x=624,13, y=55,44, z=28,84], zc['Squid'/14, l='MpServer', x=613,95, y=59,47, z=44,44], zc['Squid'/15, l='MpServer', x=621,61, y=60,06, z=45,69], yn['Bat'/17, l='MpServer', x=623,43, y=38,18, z=63,72], zc['Squid'/16, l='MpServer', x=621,40, y=57,22, z=52,20], yn['Bat'/18, l='MpServer', x=620,93, y=38,16, z=69,86], yn['Bat'/23, l='MpServer', x=626,41, y=36,10, z=51,75], zc['Squid'/22, l='MpServer', x=639,50, y=62,22, z=42,99], zc['Squid'/24, l='MpServer', x=633,53, y=50,05, z=72,16], yn['Bat'/38, l='MpServer', x=647,98, y=24,96, z=2,06], yn['Bat'/39, l='MpServer', x=640,89, y=38,93, z=-5,61], yn['Bat'/37, l='MpServer', x=642,44, y=21,49, z=-8,81], zc['Squid'/42, l='MpServer', x=654,83, y=49,13, z=71,94], yn['Bat'/40, l='MpServer', x=653,57, y=11,82, z=56,06], yn['Bat'/41, l='MpServer', x=657,88, y=12,34, z=57,51], zc['Squid'/51, l='MpServer', x=659,86, y=50,88, z=74,55], yz['Sheep'/50, l='MpServer', x=670,44, y=75,00, z=-12,34], yz['Sheep'/49, l='MpServer', x=669,19, y=75,00, z=-9,56], yz['Sheep'/48, l='MpServer', x=671,34, y=72,00, z=-5,31], yz['Sheep'/55, l='MpServer', x=674,31, y=71,00, z=5,44], yz['Sheep'/54, l='MpServer', x=676,13, y=72,00, z=-9,97], yz['Sheep'/53, l='MpServer', x=673,84, y=72,00, z=-6,50], yz['Sheep'/52, l='MpServer', x=675,53, y=71,00, z=-13,67], yn['Bat'/57, l='MpServer', x=713,48, y=39,92, z=72,72]]
Retry entities: 0 total; []
Server brand: vanilla
Server type: Integrated singleplayer server
Stacktrace:
at bxy.a(SourceFile:310)
at blh.b(SourceFile:2133)
at blh.a(SourceFile:317)
at net.minecraft.client.main.Main.main(SourceFile:121)

– System Details –
Details:
Minecraft Version: 14w25a
Operating System: Windows 7 (amd64) version 6.1
Java Version: 1.7.0_55, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 249889144 bytes (238 MB) / 523763712 bytes (499 MB) up to 954728448 bytes (910 MB)
JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G
IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
Launched Version: 14w25a
LWJGL: 2.9.1
OpenGL: AMD Radeon HD 6700 Series GL version 4.2.12430 Compatibility Profile Context 13.152.1.8000, ATI Technologies Inc.
GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Shaders are available because OpenGL 2.1 is supported.

Is Modded: Probably not. Jar signature remains and client brand is untouched.
Type: Client (map_client.txt)
Resource Packs: []
Current Language: English (UK)
Profiler Position: N/A (disabled)