ermtman:

Check this:

Go to the properties for the network connection and check to see if you have DHCP enabled to obtain an IP address for the computer having the issue scanning. I read somewhere in a previous post that DHCP releases and renews every ten to fifteen minutes or so. Each time the DHCP release and renew function occurs, it causes the printer to send out a network broadcast to "locate" all other network devices. If it does not receive a response, it will not respond to a "known" ip address, even if the network scan software is updated (as in you remove and add the scanning device again...)

If DHCP is enabled, give this computer a static IP address. That should fix the problem.

Let me know if this works.