The following procedure can reproduce the problem:

1. Install any JRE version on a Windows machine
2. Open Java Control Panel in the Windows control panel and go to the "Update" tab
3. click the "Update" bottom
4. Update JRE to the latest version

5. Now, remove the lastest version of JRE that you have just installed
6. Reopen JCP and click update again, the JCP should be of the older version of JRE
7. When the "Java Update Available" dialog shows, click the "Later" or the "X" bottom and the dialog box will not go away.

Work around.
1. Kill the jucheck.exe
2. Restart Windows
3. The user update the JRE (without a choice to cancel the update dialog box)
Note:
To direct Java 6 Update to the staging server, go to Windows registry and set the following registry key: HKLM\SOFTWARE\JavaSoft\JavaUpdate\Policy\UpdateServletURL="http://webwork.sfbay.sun.com:8081/update/1.6.0/map-1.6.0.xml"