Try changing the SATA mode to ATA in the bios first, then boot your EETech disk. You should be able to read your disk once authorised and authenticated.
Also, if you are using WinPE - you need to offline the disk before doing a "remove EE".
What was the EEPC error as there may be another solution.
Your WinPE CD is missing the SATA controller drivers for your laptop - either fix that, or put the controller into ATA/Compatibility mode.
As JM mentions - the exact error is required to properly diagnose the problem - if the "some eepc error" is "incorrect password", then decryption is not required.