Version is 1.24. I installed it off of a CD over the top of 3.5 and yes it completed successfully
with Internet tools. However when I run -2 it opens, but not 3&4.
No, that's not an Installer version. It should be something like 44.x.
I think version 1.24 is actually an ancient version from the very early 90s. Was distributed on the install disks of programs of that era, as I recall. Causes all sorts of issues with recent OS versions and larger hard disks.
Also take a look to see if Installer is in SYS:Utilities. That's another common place for it to end up. Even if you've updated the version in C:, if there's still the old version in SYS:Utilities, then something that calls "Installer" (rather than the explicit "C:Installer") could still end up using the copy in SYS:Utilities.