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.
Posted Date : 2007-08-29 04:12:30.0

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   xxxxx@xxxxx  , in zh_TW environment, it will pick up zh message, which needs to be fixed.
Posted Date : 2007-08-29 05:19:49.0

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.
Posted Date : 2007-08-29 17:16:46.0

N/A

Problem seems to be in zh, zh_TW & 'ko'(korean).  And per Michael fang, on 2000 japanese machine the font we are creating is not found causing square boxes to be shown.
Tested all other languages  and they are all working as expected.
en, fr, de, es, sv & it and ja.
Still need to test on Vista.
*** (#1 of 1): 2007-08-29 15:38:26 EDT   xxxxx@xxxxx  
Posted Date : 2007-08-29 19:39:55.0

The Japanese 2000 issue looks like this bug fixed in 5u10:
6477533 jupdate dialog renders messages as boxes on Japanese Win2K
Posted Date : 2007-08-29 21:58:39.0