laserver.prg or lalocal.prg

The message

File Not Found File "laserver.prg" does not exist., Please contact INFUSUION Support appeared when a user tried to log onto the Software.

Discovered that the connection to the Server was unavailable.  Re-established the connection to the server and opened the software.

Also check to see if any Windows updates have been done, this is known to have caused problems to users.

Is Malware Bytes installed? It is known to Quarantine the ibsapp.exe while users are in Infusion.  Reinstall Infusion.