I'm using Homesite since being first public beta (developed by Nick Bradbury, the creator of some really good pieces of software).
As i have been running it until now as admin, there have been no problems.
But when switching to non-admin, i got some OLE Exceptions.
When googling a little bit, i found an article at macromedia (they bought Allaire which themselves bought Homesite a few years ago from Nick B.) called "Windows 2000/NT users get an error when trying to launch HomeSite or Studio 4.5.1".
The articles describes what to do, when getting these OLE Exceptions.
One phrase in this article is "Each users that runs HomeSite or ColdFusion Studio needs Read/Write permissions to these registry keys".
This does not only mean that you need to have read and write access to the values in the keys. You also need to have the rights to read and create subkeys!
After realizing this, i got Homesite running as non-admin. Still a great tool ;-)