The error message "Legacy Netprobes cannot support second resolution in activeTime ...." is an error encountered due to the configured Active Time set on a sampler.
Usually this happens when an ActiveTime, for example has two scheduled periods and the second has a start time of 00:00:01, which specifies a start time of one second past midnight. The Netprobe does not and will not support ActiveTimes with a granularity better than whole minutes (i.e. a second, hence the "second resolution"); the ActiveTime is therefore NOT applied to the sampler and it is therefore active 24/7.
There are two solutions to this problem, the simpler one being the removal of the time entry of the scheduled period's End time, Simply point at the "23:59:59" field, right click and "Remove".
Another way to go about this is by just removing the seconds bit and setting it to ":00"
The second solution is to look at enabling the wider "Gateway controlled Active Times" feature - as the Gateway understands per-second ActiveTimes and can command the Netprobe to enable/disable samplers and other things with more accuracy, along with per ActiveTime set timezones.
Additional info on gateway controlled active times can be found here: