Need help with choux pastry please! My eclairs are falling .......and can't get up?

You problem could lie in a couple places. Cream puffs and profiteroles are a bit more forgiving of things than eclairs are, which could be why the same dough is producing different outcomes. If you cook too much of the water out, there isn't as much left to produce steam in the oven. Round shapes and smaller size makes this a bit easier for puffs to tolerate and overcome. But not the eclairs- which have more area to need to puff and hold up. It's also possible your eclairs simply needed a tad bit more time in the oven, to set the sides firmly. Again, a rounded shape is a bit more tolerant- circles and spheres are more stable geometric shapes for re-apportioning stress than a rectangular or square shape. So your slightly under baked puffs will be better able to stay standing than your eclairs. From the photo, I'd say that might be the problem. They could probably have used another minute or two in the baking.