Well going by what I can find on that device, it is using the slowest and oldest version of WiFi (802.11 b/g) and it is 2.4GHz. It doesn't, however, say anywhere I have looked what version of Android the device is running. Which is extremely odd.
That said, what happens, exactly, when you try to connect that device? And have you tried disconnecting all other devices, rebooting (turning off and back on) the modem/router and then try connecting that tablet before all others?