This has happened to me more times than I can count.
You build your installation and test some aspect of it. You then go back to the InstallShield IDE and make a small change, then build it again. When you do, you get all kinds of errors that make no sense. Here is a screenshot of what I am talking about:
All I did was make a small change, then rebuilt, and I got all these errors. So what’s the solution?
The solution is to just build it again and the errors will generally go away.
I don’t know why this happens. Perhaps files are locked the first time you try to build. Then they aren’t locked when you build a second time, and it succeeds. Whatever the case, I’ve found just build again and the errors usually go away.