Stuck with Sign Shops?

Where can we use the sign shops? O.o I tried to put a shop up in my land and its saying I can't use the shop, whats up?
 I know I set the shop up correctly

Are you leaving the first line blank? Here is a tutorial I pulled from the website of the plugin. I'll have a proper tutorial out tomorrow. Let me know if you are still having troubles.

Place a chest on the ground
Place a sign 1 block away from the chest (for example, above it)
On the sign, write:
First line will be filled by the plugin automatically
Price line is a combination of buy and sell prices. You need to have a price indicator (like 'B' - price that will apply to items BOUGHT by PLAYERS - or 'S' - the SELL price) near the price - the prices are separated by a colon (	Some of the possible price combinations: "B 5:5 S", "B 5", "S free"
You can find out the name of the item you're holding by doing /iteminfo
For example
	A person can buy 64 diamonds for 10 dollars and sell them back for 5 dollars from AcrobotPL

Yeah I set it up its saying "You cannot buy here"

You can't buy from your own shop though.