In the office we are using an HP OfficeJet 6310 All-In-One (donated by a friend, thanks mate!). I recently encountered a problem while attempting to scan from the device using the provided HP software bundle. The (very uninformative) error message that I received after pressing the Scan Document button was:

The communication problem is often solved by reinstalling the drivers (simply remove the printer from Printers and Faxes and click "Add Device" from the installation CD - no need to reinstall the included software) or by correcting common network misconfigurations (wrong IP, disconnected network cable, etc.). Steps for basic troubleshooting are discussed on HP's Website for USB and Network connections.

If/When the basic troubleshooting procedures don't solve the problem, there is a very involved solution for correcting the driver network connection settings posted by Ken Leon on the HP Forums (along with other useful suggestions/diagnostics in that thread).

However, in one (increasingly common) case, it may be possible to avoid the need to reconfigure the internals of the scanner drivers. If your ISP participates in DNS Hijacking, it may be prudent to rule this out as a cause of the error. It appears that the scan drivers attempt to address the device based on its hostname rather than its IP address (regardless of configuration) and when it resolves the address of the device, the DNS request gets hijacked and the scan drivers attempt to connect to the ISP server instead of the device. To diagnose this, simply disconnect the network from the Internet (and restart the router and computer after disconnecting to clear their DNS cache) and see if the error still appears. If it does, then this is not the problem, if it does not, you have found the problem. To remedy the problem, add an entry to the hosts file which associates the hostname of the device (both the name displayed in its web configuration as the hostname and its MAC address prepended with "HP" as this is often used by the drivers).