I have exactly the same FSUIPC message showing up AFTER installation of FSDT Honolulu, and I am 100% sure that I did NOT do anything else between installation and start of the Sim. So it MUST be your installation...
No, it isn't. Please, read my message again: that message COMES FROM FSUIPC!
Yes, this might have happened after our installation, no question about it, but it doesn't mean it's our installer at fault, at all. It was FSUIPC itself that *decided* there was another copy of ITSELF running which might have happened for several reasons that don't have anything to do with our installer.
One, for example, might be that FS9 wasn't closed properly the last time BEFORE you ran our installer so, Windows didn't get a chance to fully release all memory and handles and, the next time you launched FS9, FSUIPC was trying to launch its 2nd copy, because the first was still hanging out somehow.
The fact that you launched the PHNL installer in the meantime, was probably purely coincidental but I can understand why you might be misleaded into thinking that it was our installer that created the problem in the first place.
But your tip with installing the files manually worked, together with a simple reboot of the PC.
The thing that fixed it was probably the reboot, and this just confirms what I've said above about FS9 might not been closed properly, which is something that a reboot always fixes.