The HP Thin Client T5540 will not run jobs after upgrading to the CE.Net client that comes with DS 6.9 sp3 when the encryption is enabled in the client settings.
This issue has been given to development for review.As a work around you can download the latest OS from HP and reinstall it on the T5540. Make sure to have the 'Force new agents to take these default settings' either turned off or have the Encryption turned off before the CE .NET agent communicates to the DS for the first time. Also delete the machine from the database and allow it to add itself in as a new client.
DS 6.9 sp3 - Altiris CE >NET Agent version 6.9.430
HP Thin Client T5540
Image version 6.03.631
Microsoft Windows CE: 6.00