Microsoft’s Peter Saddow, who is a Program Manager on the SQL Server Setup team has a post in the SQL Server Setup blog that explains an occasional error that you can see when you install SQL Server 2008 or SQL Server 2008 R2 August CTP on Windows 7 that looks like this:
“Invoke or BeginInvoke cannot be called on a control until the window handle has been created.”
His advice is that if you do see this error, you should just run setup again, and you probably won’t see it again. It is due to be fixed in an upcoming CU for SQL Server 2008 and in SQL Server 2008 R2. I have seen this error a couple of times myself, so it is nice to know the explanation.
This is separate from the two warnings you will get if you try to install a non-slipstreamed version of SQL Server 2008 onto Windows 7 (which you can safely ignore, as long as you install SQL Server 2008 SP1 after the RTM installation).