I was distributing an .exe for beta testing, the first two to test were Win2K "Domain Admins" who had full rights to everything on the server.
When another user without those rights ("Staff") attempted to run the .exe, it stopped dead, "File Access is Denied" on the line This.oMMFactory = CREATEOBJECT("cAbstractFactory") in cApplication.CreateAbstractFactory.
The network administrator has repeatedly reset the rights for Staff to give them full rights to the directory, but the error message refuses to go away.
Moving the files to a local drive did not resolve it, copying the class libraries was equally unsuccessful.
There is no short answer for this and since you haven't mention this I'll recommend you start here: Look in the Mere Mortals Framework Dev Guide and search "preparing applications for distribution".
Let us know if you find something that you've missed.