The agent in the following IBM technote will resolve this issue. I have also used this agent with the 8.0.x and 8.5.x versions as well as the versions listed in the technote….
‘Your availability time range is invalid’
Apparently, Lotus Notes is looking for a 24 hour time format, even though as soon as you click away from the entry it returns it to a 12 hour format display. I was able to fix the issue by entering in my availability using a 24 hour time and the associated AM/PM needed. Odd, but it worked.