The error was
"The module "X:\path\VB6IDEMouseWheelAddin.dll" was loaded but the call to DllRegisterServer failed with error code 0x80004005.
For more information about this problem, search online using the error code as a search term."
Fix for the problem:
First Download and unzip it to any locatoin, keep the location in mind.
This is how I had to fix it, I had to create a batch file and then run it as administrator. How do you do it?
Go to Run, i.e.) Windows Key + R and type in "Notepad" without quotes and it should open up.
Or key in "Notepad" at Start Menu Search, you should get it
Now in the notepad window, enter the following,
Where X is your Windows Drive, in my case 'C' drive and Y is the drive where you have your file, i.e., where you unzipped it, suppose it is in G:\MouseWheel\VB6IDEMouseWheelAddin.dll then put that in there between the quotes.
Now its simple, save the file as .BAT file and not .TXT
In Dialog select "All Files" from dropdown list and Type filename.BAT
Now right click on your saved BAT file and Run as Administrator, that's it. It's now loaded.
Now the remaining part in VB6, open up VB6.
Go to Add-Ins -> Add In Manager
Select MouseWheelFix and check the boxes below "Loaded/Unloaded" and "Load on Startup".
That's it. You are good to go, mouse will now work fine. :)