I don't know if this will work for everyone, but I was able to solve my post installation dll error message problems as follows:
1. Deinstall all loaded Everquest Programs and Versions using the Add/Remove Program function in the control panel.
2. After the Programs are uninstalled, use the Windows Explorer to locate the Everquest folder (it should be in the Windows/Program Files directory, unless you have deliberately installed it elsewhere)
3. Delete the Everquest folder (and thus everything remaining in it).
4. Re-install the original Everquest program. Do not install the Direct X.
5. Re-install the Shadows of Luclin upgrade directly (i.e. it is not necessary to re-install either Kunark or Velios upgrades). Make sure to check that you want the Direct X 8.0 installed.
6. Connect to the internet.
7. Execute the Everquest icon on your desktop (don't use the "Test Everquest" icon). The program will then begin checking all your files and begin downloading the necessary patches (including the eqgrfx_dx8.dll file).
All of the above assumes you already have a compatable graphics and sound card and the drivers loaded. Good luck. AW