I just installed 5.4.3 and have attempted to install additional packages using "Install from Repository" from http://bitdojo.org/acs-admin/install/
Result:
Take me back where I was (before the error)
Couldn't get the package list. Please try again later.
while executing
"error "Couldn't get the package list. Please try again later.""
(procedure "apm_get_package_repository" line 19)
invoked from within
....
I ran into the same problem last Monday (while demo-ing in front of an audience).
If I browse to the repository (https://openacs.org/repository/) I see that the only channel available is 5-5 (although there are no packages listed in that channel).
What gives?