MSComCt2.ocx run time error on only some systems

Dear Experts;

These may be two different issues with the same presentation. But as the error is identical I'm wondering if there isn't a single fix.

I have a VB6 application that runs fine on most systems.
Lately - I've been getting reports users are getting 'mscomct2.ocx is not registered or one of its dependencies is missing'.

On System 1:  Win7; 32-bit
* the app used to run fine; there have been no changes that I'm aware of.
* I distribute the app with mscomct2 into Sys32; (the distribution checks for sysWow or sysWow64)
* Mscomct2.ocx has been manually registered with regsvr32 and indicates sucess - the error persists.
* A different, recently compiled application which also uses mscomct2 does not error.
* The erroring app uses an old .dll that was compiled with mscomct2.ocx years ago (code is gone). Checking the version of prob ocx vs. the current app  mscomct2.ocx; they don't match (one is 6.01.9811; the old is 6.01.9782).
* So my answer here may be to unregister current/rename it/copy in old/register it/run program and copy & un/re-register all back to original status.

System 2 is more of a mystery.
* It was recently upgraded. I'm waiting for information as far as what that means, but I think it has been upgraded from Win7 to Win8.
* Before upgrade, the app ran fine.
* I know mscomct2.ocx doesn't come included in Win8 so I again distributed the component w/ registration.
* The user reports the error continues.
* I haven't tried manual registration on this system yet.
* I'm considering removing the controls from this app and using either a third party (I need DatePicker); or coding the datepicker functionality by hand.)
* If I go this route, a suggestion for a 3rd party DatePicker for VB6 it would be appreciated.

Any ideas on what is going on w/ this control and better ways to manage it?
Thanks
klheitz