A Floating User license is shared by a group of users within the same network. This kind of license is hosted on a dedicated computer, called License Manager PC, which controls the usage of AQTime copies over the network.
When you start AQTime, it searches for the License Manager PC on your network in order to request permission to run. AQTime displays this message if the License Manager PC that AQTime used last time is not available, and AQTime did not find other License Managers in your network.
To resolve the problem, follow the recommendations provided in the License Check Problems -- Node-Locked Licenses topic, and then try to launch AQTime once again.