Problems deploying VB6 App for all OS's

I'm new to this forum and hope that somebody can help me with a vb6 deployment problem. I am using the VB6 package and deployment wizard to create my downloadable installer. I have finished a VB6 app c/w an msaccess backend.

When my application is installed on a windows xp machine the installer pops up a question window asking if the user wants to update a file with an older version and a reccomendation to keep the existing file. The Dll's are:

itircl.dll - microsoft infotech IR local DLL
itss.dll - microsoft Infotech Storge system library
hhctrl.ocx - microsoft html help control
scrrun.dll - microsoft script runtime
mswstr10.dll - microsoft Jet sort library
msjint40.dll - microsoft jet engine

This happens six times and is quite annoying and confusing to the users although the application installs and runs okay on ME/2000/XP machines.
Do I really need to deploy these dll's with my app? Do I need a more expensive installer packager that can detect the operating system and only install the files that are needed?

Do I need to include MDAC for the win98 pc's in my install package? I know that I don't need it for ME/2000/XP. Problem is I can't have two different installer downloads on download.com where my application resides. How can I Install for all OS's from one installer?

I really want my application to be useable on win98 pc's but am afraid that it might produce serious problems as the following installation test indicates.

I tried installing my application on a windows 98 first edition pc the installer says that a couple of files are out of date and will need to be updated before the install can continue. It then updates the files reboots the PC and then the pc that i installed it on will not properly run win 98 anymore!

I have a lot of knowledge about vb6 now but am really struggling with this deployment part. I would be extremely grateful for any help from this forum.