Dear Paul,

Updating Tiger and Java may solve the problem as it is confirmed that the JUDE for Mac OS X works fine on the environment described as below.

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Mac OS X 10.4.11 (8S165) 1.5GHz PowerPC G4
512MB DDR SDRAM java version "1.5.0_13"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_13-b05-241)
Java HotSpot(TM) Client VM (build 1.5.0_13-121, mixed mode, sharing)
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So please try launching JUDE again after updating Tiger and Java.

If you are still unable to launch JUDE, please let us know again.

Thanks,
Satomi