"Cannot start NX statistics" when installing NX Server 3.5.0 is normal behaviour because statistics are disabled by default via the EnableStatistics configuration key in the file server.cfg.

The statistics are collected by the nxstat daemon in the background.
This daemon can be used to produce statistics about the NX services and the node host machine either for localhost and any of the available nodes when the load balancing is enabled.

When running the NX Enterprise Server this feature is not relevant since the load balancing functionality (multi-node) can only be enabled using the NX Advanced Server.