tv script erro save

integer channel_dialog;
list buttons = ["Off"];
key ToucherID;
string message;
integer listenID;
string category;

get_categories()
{
    integer n = 0;
    while (llGetInventoryName(INVENTORY_NOTECARD,n) != "")
    {
        buttons = buttons + llGetInventoryName(INVENTORY_NOTECARD,n);
        ++n;
    }
}

get_videoList(string category)
{
    integer NumLines = osGetNumberOfNotecardLines(category);
    integer n;
    for(n=0;n<NumLines;n=n+2)
    {
        string NoteCardLine = osGetNotecardLine(category,n);
        if (NoteCardLine != "")
        {
            buttons = buttons + NoteCardLine;
        }
    }
}

play_video(string vid_url)
{
    llSetPrimMediaParams(2,
        [
            PRIM_MEDIA_ALT_IMAGE_ENABLE, 1,
            PRIM_MEDIA_CURRENT_URL, vid_url,
            PRIM_MEDIA_AUTO_LOOP, 1,
            PRIM_MEDIA_AUTO_PLAY, 1,
            PRIM_MEDIA_AUTO_SCALE, 1,
            PRIM_MEDIA_PERMS_CONTROL, PRIM_MEDIA_PERM_NONE
        ]);
}

string get_video(string title)
{
    integer NumLines = osGetNumberOfNotecardLines(category);
    integer n;
    for(n=0;n<NumLines;++n)
    {
        string NoteCardLine = osGetNotecardLine(category,n);
        if (NoteCardLine == title)
        {
            NoteCardLine = osGetNotecardLine(category,n+1);
            return NoteCardLine;
        }
    }
    return "";
}

default
{
    state_entry()
        {
        llClearPrimMedia(2);
        channel_dialog = -1 - (integer)("0x" + llGetSubString( (string)llGetKey(), -7, -1) );
        state main_menu;
        }
}

state main_menu
{
    state_entry()
    {
        buttons = ["Off"];
        message = "\nChoose a category.";
        get_categories();
    }

        touch_start(integer num_detected)
        {
            ToucherID = llDetectedKey(0);
            llDialog(ToucherID, message, buttons, channel_dialog);
            listenID = llListen(channel_dialog, "", ToucherID, "");
        }

        listen(integer channel, string name, key id, string message)
        {
            if (message == "Off")
            {
                state default;
            }
            else
            {
                category = message;
                state sub_menu;
            }
        }
}

state sub_menu
{
    state_entry()
    {
        buttons = ["Off"];
        message = "\nChoose a video.";
        get_videoList(category);
        llDialog(ToucherID, message, buttons, channel_dialog);
        listenID = llListen(channel_dialog, "", ToucherID, "");
    }

    listen(integer channel, string name, key id, string message)
    {
        if (message == "Off")
        {
            state default;
        }
        else
        {
            play_video(get_video(message));
        }
        state main_menu;
    }
}