Hi,
I just moved to GUIMiner-Scrypt today and I am getting an Unusually high number of Invalids with this
636.14 kH/s Speed 663,538 Valid 16,176 (2.38%) Stale 77,264 (10.21%) INvalid 0 Blocks found
This is on a 7950 Running GUIMiner-Scrypt with host litecoinpool.org:3333 Stratum on and 7950 Preset option (high Usage)
Check your settings. Usually a shit ton of invalids are caused by your intensity being set too high.