That's a nice question, anyone who knows the answer?
Question: is it possible to edit/change the text box that appears when a software distribution task is completed or failed!?
Not really supported, so might change any version-change from LANDesk, but the HTML is downloaded from Program Files\LANDesk\ManagementSuite\ldlogon\html to the agentfolder on the device. It contains the HTML and the .js file from your language with the text-string.