A few weeks ago while upgrading my IBM Sametime servers to 8.5.2 IFR1, I ran into an issue upgrading the Sametime System Console.
ADMC0016E: The system cannot create a SOAP connector to connect to host hostname at port 8881.
After a bit of searching I came across the following IBM Technote that outlined the problem was due to me having IBM i 7.1 PTF Group level 8 installed, which contains JDK6032 SR10 (PTF's SI45555 and SI45463). Due to a Java incompatibility problem, these PTF's will cause an upgrade to Sametime 8.5.2 IFR1 to fail.
What I had to do was remove those two PTF's (using command RMVPTF) and three other dependant Java PTF's on my system (SI30318, SI45340 and SI45339), upgrade all the Sametime servers to IFR1, then load and apply those PTF's again after the upgrade.
It might sound like a pain, but I upgraded all Sametime servers (Sametime System Console, Community Server, Proxy Server and Meeting Server) in about 4 hours total. That's pretty good time.