You are using wrong versions of MSI AB that don't include the 2 missing .dll files. No versions after 2.2.1 will work since they don't include the 2 missing dll files and no Catalysts after 12.4 I believe include them either. This is why it's not working for you.
1. Before you do anything, go to your MSI Afterburner main folder:
C: \Program Files (x86)\MSI Afterburner
Do you have these 2 files in this folder?
atipdl64.dll
atipdlxx.dll
If you do
not have these 2 files, you need to download them and paste them into the main MSI Afterburner folder. The easier solution is just download
MSI Afterburner 2.2.1, install it. This program includes the 2 missing dll files by default. If you wish to use newer MSI AB versions after, you can extract them and repaste them into newer MSI AB versions. For now though just use MSI AB 2.2.1 to get it to work and later you can re-install to a newer version.
2. The next step is for you to find the MSIAfterburner.cfg file in the main MSI Afterburner folder. Take this file, cut it and paste it onto the desktop. Right click it, Open with ... Notepad.
Drop 2 lines under the heading [ATIADLHAL]
UnofficialOverclockingMode=1
UnofficialOverclockingEULA=I confirm that I am aware of unofficial overclocking limitations and fully understand that MSI will not provide me any support on it
File --> Save As --> Override the .cfg file when it asks you. Now take this file, and make sure it's still called MSIAfterburner.cfg, and paste it back into the main MSI Afterburner folder where you already have the two .dll files I outlined above.
3. Download Asus GPU Tweak (should be able to find it in Search on Asus.com website). Once you open this program, go to Settings --> Tuning --> Tune Settings --> check mark "Overclocking range enhancement", press Apply. The screen should flash black. Now you can close Asus GPU Tweak as you don't need it again. You can go into the Main menu and disable this program from starting on boot.
Restart the computer. Now open MSI Afterburner and the GPU voltage and all the overclocking sliders for GPU core and memory should be unlocked.