I pulled this solution of another forum when I googled "Error code: -6001"
Code:
Delete the folder "0701" in the following directory :
"C:\Program Files\Common Files\Installshield\Professional\Runtime\"
Once deleted, you should be able to install the game normally.
This will NOT effect any other applications or programs on your system.
It seemed to work for some people, just make sure you have view hidden folders on, and search for the folder if it's not located where its suggested.
Also... this is an EQ1 emulator, was it a typo where you put EQ2?
Let us know how you make out.