How to activate iPad 1 3g without sim card

Hi,

I have been given an original iPad 32GB 3g. I restored it to factory settings so I could set it up the way I liked id. When it restored I attempted to restore without a sim card in. I selected a language, a country and wifi network. Then i click next, and this message pops up on the iPad screen and iTunes.

Unsupported SIM

The Sim card you are attempting to use is not a standard 20 digit ICCID that is required by the iPhone. This is not a hardware issue with the iPhone. Please contact your carrier and obtain a standard SIM card.

The iPad is running ios5.

Has anyone seen this message before. I thought I could use this without a sim.