Okay boss U right. Is better to read the manual for these options as well.
Action: SetOption can be used to configure certain options of the KiXtart script engine

This will work.
Code:
Break On

Dim $SO

$SO=SetOption('Explicit','On')

$SO=SetOption('NoVarsInStrings','On')

  

Dim $server

$server = "MyServer"

USE Z: "\\" + $server + "\share"