Setting up first time miner having issues / Litecoin

[greek]

I read through all the guides and installed the latest AMD SDK and 13.1 Drivers for my 2x 7950's.  I installed my wallet and synched up and registered at a pool where I setup a worker.
I'm attempting to connect using guiminer, but eventually fails with an error -5: Enqueueing kernel onto command queue gpu0 failure, disabling!  So I try another program reaper and I configure the reaper.conf file as follows:
kernel reaper.cl
save_binaries yes
enable_graceful_shutdown no
long_polling yes
platform 0
device 0
device 1

mine litecoin
and litecoin.conf as
host ltc.kattare.com
port 9332
user x
pass x

protocol litecoin

worksize 256
vectors 1
aggression 20
threads_per_gpu 1
sharethreads 32
lookup_gap 2
gpu_thread_concurrency 21712

I then run reaper and receive this error:
buffer is too big and either need to raise lookup gap or lower thread concurrency (I've lowered the thread to a extremely small number but I still receive this error.)

My system setup:
XFX P1-850B-BEFX 850W PSU
2 SAPPHIRE 100352-3L Radeon HD 7950 3GB 384-bit GDDR5
E8400 Wolfdale 3ghz core 2 duo cpu
EVGA 680i motherboard
4gb ddr2 ram
250gb hdd sata
Windows 7 32-bit (complete fresh stage)

[sinergy]

Hi there, I have similar problem with CGMiner and "error -5: Enqueueing kernel onto command queue gpu0 failure, disabling!" (in mine case for two GPUs without crossfire). This seems to have happened since I tried to use "setx GPU_MAX_ALLOC_PERCENT 100" in Windows in order to increase the maximum thread concurrency. Greek, did you modify this value as well?

I tried to delete the registry keys for GPU_MAX_ALLOC_PERCENT but it didn't help. Now CGMiner is always showing this and stops when I try to mine litecoin. Bitcoin mining works fine though.

I tried reaper as well but it didn't work even with 6144 thread concurrency. I also tried GUI Scrypt miner which appears to be based on CGMiner as well and it works fine with 8192 for thread concurrency.

I am using Windows 7 Ultimate x86_64 and tested it with cgminer 3.0 and 3.1 (reaper was the latest version) but no difference. Does anyone know how to fix this?