Sounds like you are on track at this point, but for the sake of completeness I would just note that the HRESULT you got translates to:
0x80244019 -2145107943 SUS_E_PT_HTTP_STATUS_NOT_FOUND Http status 404 - object not found
I have never seen that occur before, but if you are using WSUS, then it would seem to imply that the actual update content is missing from your WSUS server despite the fact that the update exists in the catalog database on your WSUS.