The time frame is unknown. Hints in the story tell us that the podcast starts during 2008 during the time of it's release on the internet. Not many "Current" events are spoken of by Simon Richards.
If this is the case that the podcast started during 2008, it would be taking place in a alternate timeline then ours. Meaning that some time during 2008 the Among the Dead time line branched off of our timeline.
Others thoughts is that the time frame takes place much further in time then ours. Around 2025 or 2030.