A further problem can be that the iPad is not connected to the same network as the PC or MAC. It is of course imperative that both devices are in the same network. The iPad has Wi-Fi and the PC can be connected to the network via a LAN cable or WiFi.
On some versions of Windows 7, especially when many small files are copied, we noted a remarkably slow transmission speed. The solution for this problem is already described in the user guide, which is available in MobiFolders under "Help". Click here if you want to read this chapter.