Depends what you mean. If a basic Wooden Door isn't opening, then something fairly serious is wrong.
If you're having trouble opening an Iron Door, they cannot be opened normally by interacting with them. You need to set up a button, pressure plate, lever, etc, next to them, and use that to open it.
You might have to update your minecraft
What do you mean? Minecraft saves automatically all the time, so I don't understand how that can be a problem.
Settings for MC.
The pocket edition of minecraft doesnt have crafting, therefore doesnt need one. Its a crafting table btw.
There is an option on the downloaded version that says "play offline" click that.
At the login screen, press options and force update. Then try again. If that doesnt work, try deleting %appdata%\.minecraft and change your password.
Minecraft 1.5 and earlier: Right Click Minecraft 1.6 and newer: Left Shift I am guessing you will be playing a new version, so press shift. If that doesnt work, right click.
im not sure but if it say outdated laucher try to delete minecraft and then download it again if this doesnt work try to rename it to minecraft.exe or search on youtube
power door lock actuator is broken and not letting the key raise the lock button
It is unlikely you will be able to use your warranty to get a door handle that doesn't work. Though you should have no problem getting a door handle that does work. Call the retailer that supplied the item.
pull the handle. if that doesnt work check the child safety lock in the sil.
You may need to download the newest version of Java for minecraft to work. Or maybe your computer can not handle it.