include a script that is on the network

I would not think a URL would work.  I remote access may also require each user ID have share access to the remote file and would definitely need a network connection.  I would not think using a UNC a network uneverasel access address a good thing to use in Photoshop scripts.

This works for me.

N.B. the first line of you script MUST have #target photoshop; as this is used to find the begining of the script!

var HTTPFile = function (url,port) {
          if (arguments.length == 1) {
                    url = arguments[0];
                    port = 80;
          };
          this.url = url;
          this.port = port;
          this.httpPrefix = this.url.match(/http:\/\//);
          this.domain = this.httpPrefix == null ? this.url.split("/")[0]+":"+this.port :this.url.split("/")[2]+":"+this.port;
          this.call = "GET "+ (this.httpPrefix == null ? "http://"+this.url : this.url)+" HTTP/1.0\r\nHost:" +(this.httpPrefix == null ? this.url.split("/")[0] :this.url.split("/")[2])+"\r\nConnection: close\r\n\r\n";
          this.reply = new String();
          this.conn = new Socket();
          this.conn.encoding = "UTF-8";
          HTTPFile.prototype.getFile = function(f) {
                    var typeMatch = this.url.match(/(\.)(\w{3,4}\b)/g);
                    if (this.conn.open(this.domain,"UTF-8")) {
                              this.conn.write(this.call);
                              this.reply = this.conn.read(9999999999);
                              this.conn.close();
                    } else {
                              this.reply = "";
                    }
                    return this.reply.substr(this.reply.indexOf("#t")-1);
          };
}
var estkFile = new HTTPFile("http://www.yadayada.com/folder/fileName.jsx");
eval(estkFile.getFile());