Tested following binary to verify 6581817 fix and found problem.
http://j2se.east.sun.com/~rkaja/jucheck.exe

On Windows 2000 pro, Japanese, the update dialog displays garbled text. Please refer to attached screenshot.
On Windows XP pro, Japanese, the same dialog is rendered fine.

Test procedure:
1. Install 6u2 from java.com (get java auto install).
2. Set HKLM\software\Javasoft\Java Update\Policy\UpdateServletURL registry (string) value to map.xml file: http://java-g11n.sfbay/j2se/6u3/l10n/jupdate/map-locale.xml
3. Copy http://j2se.east.sun.com/~rkaja/jucheck.exe to your locale machine and run it to get the update dialog.
On XP zh_TW (multilingual), the dialogs are garbled when locale.xml sets xml:lang="zh" for S.Chinese. When it's set to "zh_CN", English message is displayed. The section of xml:lang="zh_TW" is skipped and not used. According to ###@###.###, in zh_TW environment, it will pick up zh message, which needs to be fixed.
On XP zh (multilingual), the dialogs are also garbled when locale.xml sets xml:lang="zh" for S.Chinese. When it's set to "zh_CN", English message is displayed.