Exception calling Cipher.getInstance("AES")

When I call Cipher.getInstance("AES") it is fine on my development PC but throws an exception on some PCs saying it can't find an AES provider. The Java 5 java.policy/security files in the lib\security folder are identical on both systems. I think the difference is that it works if the Java 5 SDK is installed, but not if it isn't, even though the JRE contains the AES provider (sunjce_provider.jar). If I add <JRE path>/lib/ext/sunjce_provider.jar to the classpath when launching my application, it finds the AES provider, but this causes another non-fatal but annoying (and scary to operators) JVM error box to pop up.

It's not good to require the Java 5 SDK to be installed on each client PC, so I'd like know how to get this to work correctly with just the Java 5 JRE.

I'm running Windows XP, as are most clients. Apparently this error does not occur on Linux.

This turned out to be a problem with an incorrect install of Java. This particular version of Java got installed using a non-standard process that did not get everything right. When I used the regular Java install it works fine!