TextLayout bounds can't render correctly and characters are rendered as square box

platform: ubuntu 8.0.4
locale: zh_CN.UTF-8
build: open jdk6 b05

TextLayout bounds can't render correctly and some characters are rendered as square box when we ran TextLayout2DRenderTest for open jdk6 b05 on ubuntu 8.0.4 .
openjdk_ubuntu_zh_CN-TextLayout2DRenderTest.jpg is this bug screenshot in attachment.
businessjdk_RedHat_TextLayout2DRenderTest.jpg is correct screenshot in attachment.

To reproduce the bug:
1. Install open jdk6 b05
2. Install test tools GS-Tonga_12.zip
3.Set test environment
4. run runnit.sh script: sh runnit.sh -keywords:"zh_CN&&manual"
5. Follow to TextLayout2DRenderTest.
6. Note magenta TextLayout bounds and some characters are rendered as square box

Or reproduce the bug by TextLayout2DRenderTest.jar in attachment:
1. Execute "$JAVA_HOME/bin/java -jar TextLayout2DRenderTest.jar"
2. Note magenta TextLayout bounds and some characters are rendered as square box.