the source button on your post resulted in an error.
a good way to handle sliding doors is to know the players object number say 1
and the doors might be objects 2-10
this way you can perform a distance check, if the players object is within a certain
radial distance to the sliding door object then activate the door.
Distance Functions are everywhere in this forum, you will find many distance functions for 3d and 2d usage.
You can however use 2 dimensions of detection in a 3d space, so crimping a 3d distance function to only look across the X and Z dimensions helps to improve speed when distance checking with varied objects.
if that makes no sense just read it later after you have some distance functions to look at.
sliding of the door is to move the door in one of the dimensions and stop after a set distance
for example the doors size was 10x10x3
if the door was facing us so it slid across the X dimension (thats left to right) and we want to slide it to the right or positive X dimension space.
since we know the object is 10 units in the X dimension we could slide it 10
and it would slide exactly to the left one whole door unit.
im not on a pc at the moment, i had some examples of sliding doors at home, ill try and post them later, but it may be a few days before i get back there.
If no-one gives your an answer to a question you have asked, consider:- Is your question clear.- Did you ask nicely.- Are you showing any effort to solve the problem yourself 
