Try to Uninstall PHNL first, and REMOVE its folder under FSX\fsdremteam\PHNL (if it's still there) and install the full version.
Uninstalling/cleaning/reinstalling did not work here, either.
There were five files left over after the uninstall, I deleted the PHNL folder, reinstalled, and I continue to get the "You have an old version of Honolulu Scenery..." popup. It warns that the scenery will deactivate when the area is entered, but it seems to still work anyway.
If I uninstall and reinstall V1.0 and the V1.03 update I do not get the error.
I noticed something else weird yesterday...the time elapsed and time remaining values on the setup/installer (while downloading/installing bglmanx.dll, bglmanx.dat, and couatl.exe) showed 7101 weeks, 3 days. The reinstall I just did does not do that, but I saw it at least twice while trying to get things working yesterday. The PC clock was OK...no other programs were/are having issues with date/time.
Colonel, USAF (ret)
ATP IMEL Gulfstream II-III-IV-V
Colorado Springs, CO