HI Uwe, I have the exact same issue as you except the following differences in setup.
It's AIX and with 2 systems on the same host; dev and qas, and I have recently updated the dev system without any problems just a few days ago, no patches on AIX in between, but then when I start with qas, I get those errors in the sapstartsrv.log of saphostagent. I have reported it to SAP and are awaiting a response, but if someone has any ideas meanwhile, please let me know.
After credentials are put in, a http 404 error appears, and at the same time those entries are written to the log with HTTPProxHan 604.