How do open the door in canalave city that says the door is tightly shut it appears impossible to open on Pokemon pearl?

The door can not be open unless you have a membership card...

Q: How do I get a membership card?

A: Simple, you can't, 'cuz it was(I believe) a limited time-only even t at wal-mart. BUT! You still can get it through cheating(cheap) or, you can get someone who actually got a arceus(awesome)/shaymin/darkrai event item. Why? Because you can do a mystery gift trade. Mystery gift? Check it somewhere else.