Symptom:
User computers were successfully found, added to the list, connected and controlled before restart of User computers. After restart, Administrator Module either cannot connect this computer or connect other computer in the network (than was found originally).

Reason:
It seems like your computers use dynamic IP addressing.
Please choose correct addressing mode. In Administrator Module: 

• Click [N] -> Options -> Control Options menu command;
• On "Connections" tab, please select "Dynamic IPs. Create connections using network name" mode.
  Click OK button.
• Delete ALL connections from a workspace: press Ctrl+A on a keyboard and then press Delete key.
  
• Scan for new connections again.