Hi,
Failed to find content ID DUS0015E.19 in content library on 'E:\SCCMContentLib'
From the error message, it seems the content is not distributed to the DP. Normally, re-distributing or updating the contents on the DP's will fix the issue.
In addition, when we create a stand-alone media, we can opt to CD/DVD and then burn the .iso into the USB stick, using some free tool, for example, rufus, which makes the process more smooth. Here's the example screeshot for your reference:
Hope the above information helps.
Regards,
Alex Zhu