When attempting to install Service Pack 1 on SQL Server 2008, I keep getting the following error:
"Invoke or BeginInvoke cannot be called on a control until the window handle has been created."
There is a flaw with various retail releases of SQL Server 2008 that can cause this problem. Sometimes rerunning the Service Pack multiple times with no other windows open will eventually get past this error.
However, on some systems the only way is to obtain a Hot Fix from Microsoft. In our case, we had to request the Hot Fix associated with KB 975976 entitled "Cumulative Update Package 8 for SQL Server 2008". This is the URL we used to obtain the update: