Windows XP SP3, german installation, JDK 6u30 or JDK 7u2 installed (the issue can also be reproduced with earlier update releases).
Testcase with 7u2:
Open ControlPanel, "Update" tab, click on "Jetzt updaten". Nothing happens. No error message, no dialog.
The action event that has been added to the "Jetzt updaten" button actually tries to launch
C:\Programme\Common Files\Java\Java Update\jcheck.exe
However, that file does not exist on my german Windows XP. Actually "Common Files" is called "Gemeinsame Dateien" on my box and jcheck.exe is located in
C:\Programme\Gemeinsame Dateien\Java\Java Update\jcheck.exe