The tags need to case sensitive - the tag you sent worked.

<object id="simpleControl1"
classid=bin/MyControl1.DLL#mycontrol1.UserControl1
height="300" width="600" >
</object>

I remember these things - they don't like spaces and all sorts of stuff. Any little inconsistency and it fails, spaces in the dll name was one of them.

I remeber when I didi an office version (interop with word) you had to make sure you didn't actually execute any code until the flaming thing appears in the web  page - at least then you know it works. Then do things on clicks of buttons.

I'd also like to say that I've set up all my old ones on my hard drive again and yours is the ONLY one that does work. God knows why. I think half of them are in beta2 code, the vrt dir now has a different name so there goes me path .... and from what I can remember IIS was very temperemental about whether or not it was going to display  them or not. I thought it had a bug but then it all sorted itself out. Now none of them work (again).

But you CAN make any form into one of these and they WILL download supporting dll's and you DON'T need to remove "main" and you CAN use an .exe in place of the dll.