It is possible to raise the skybox of a level in sapien?
Cos i was modded this level and i made it you started on top of it and had to walk along the top of the walls and drop down into a certain place and begin the fight. I was like okay here goes...i'm not walking on the wall?....I jump out into thin air...damn...invisble floor/skybox

Either import the .gbxmodel of the sky you are using (make a copy FIRST. Never edit a tag in such a way without first making a copy to edit and leaving the original intact in case you mess up) into your map's scene, and raise the sky up until the sky no longer covers your map at all, or just lower your map so it doesn't interfere with the sky.

What exactly are you saying...?

Can this all be achieved in sapien? And how do u open a gbxmodel into sapien?

Not possible in Sapien. Sapien only loads models that are finalized. If you need to make changes to them (and you do), you have to do it in max/gmax.

Using a .gbxmodel importer (search this site), import the .gbxmodel of the sky you want to change. Make sure you import all nodes and frames and whatnot (if you use The Ghost's importer, and I strongly recommend you do, there are options for this, checked by default). Now, in this scene, you should have your sky's model imported. It's more than likely a hemisphere with several planes around it.

To make your changes, import your map (the model you made in max) for scale. Move your sky's FRAME (say again: FRAME. It's probably called frame sky or something, and it will be at the TOP of the hierarchy). Move the FRAME up until the sky is in the position you want it in. Make sure your map is also in the position you want it in.

When your sky is as you like it, delete your map, and export your new sky. Now build your sky until it is ready to be applied to a .scenario, and apply it like you would any other sky. If you did everything right, your sky should line up correctly, as it did in gmax/max.

If you don't know how to rebuild your new sky, search for a tutorial on this site and skip the creation, bitmap making, and other beginning steps, since you are only editing an existing sky's position (however, if you change anything else, I'd take a look at the tutorial to verify you performed all the appropriate procedures).