I don't know whether this is the correct place to ask such a question, but I am dealing with this problem for a couple of days.
Take for example the script http://math.stanford.edu/~stange/scripts/tate_via_nets.gp.
What I do is: copy the script to a txt file and name it tate_via_nets.gp. Then I go to my sage notebook and choose above the option 'gp'. In the first block I write
where filename is the whole path of the file tate_via_nets.gp (so C:....\tate_via_nets.gp) and "evaluate" it. But then I get the error
* at top-level: read("/home/sage/.sa * ^--------------------
* read: error opening input file: `C:\Users...\tate_via_nets.gp'.
If you see me doing things wrongly please let me know it :-) I am working with sage 4.7.1
EDIT: I have changed the "source" of the problem