It is because eventhough you have Java 5 installed, the JVM running may be different.

Try typing this in the console window: java -version.
It will give you the Version of the Runtime Environment.

Or, if you are using an IDE, then you need to enable Java 5 support.
In Eclipse, You can add Java 5 in Window > Preferences > Java > Installed JRE’s.
and/or, Set the compiler compliance level to 5.0 (Window > Preferences > Java > Compiler)

In Netbeans, you can use (Tools -> Java Platform Manager) to check your default platform.

RTHDCPL.EXE – Illegal System DLL Relocation : The system DLL user32.dll was relocated in memory. The application will not run properly. The relocation occurred because the DLL C:\WINDOWS\system32\HHCTRL.OCX occupied an address range reserved for Windows system DLLs. The vendor supplying the DLL should be contacted for a new DLL.

I was confused and wondering what happen to my computer because I didn’t do anything, but all of the sudden on the next time I reboot my PC, this error suddenly pop up. I tried to Google the problem everywhere, there’s only a little bit of solution, until there’s one time that there’s someone that actually HAVE the EXACT same problem with me and write something on his blog on how to solve this problem. HAHAHA! And yeah, I’m doing the same thing right now, because there’s only a little source out there.

Anyways, this problem is caused by the Microsoft’s Automatic Update, the solution to this problem itself is just posted for about 2 days ago. Just follow this link to update your computer.