Yes this works but you first have to remove the add-on restart Firefox then delete the fast dial directory by going to help,troubleshooting etc and open container and delete the Firefox directory. Simply download file and install the xpi file and voila it works in Firefox 7.0.1!

No it doesn't work. I just did a clean install of FF 7.0.1 and tried to install FastDial 3.5.1. It didn't work. Now I followed your steps and removed the fastdial extension directory and reinstalled it. Didn't help either.

*** chrome/content/bookmark.js 2011-07-01 14:05:54.000000000 +0200
--- /extensions/[email protected]/chrome/content//bookmark.js 2011-10-07 18:22:00.793552060 +0200
***************
*** 73,78 ****
--- 73,87 ----
}
}

+ function getURI(id) {
+ try {
+ return livemarkService.getFeedURI(id);
+ }
+ catch(e) {
+ return "place:folder=" + id;
+ }
+ }
+
this.isQuery = function(url) {
return /^place:(?!folder)|^place:.*&(?!sort).*/.test(url);
};
***************
*** 86,92 ****
container.containerOpen = true;
for (var i = 0; i < container.childCount; i++) {
var item = container.getChild(i);
! var feedURI = livemarkService.getFeedURI(item.itemId);
if (item.type != item.RESULT_TYPE_SEPARATOR) {
bookmarks.push({
id: item.itemId,
--- 95,101 ----
container.containerOpen = true;
for (var i = 0; i < container.childCount; i++) {
var item = container.getChild(i);
! var feedURI = getURI(item.itemId);
if (item.type != item.RESULT_TYPE_SEPARATOR) {
bookmarks.push({
id: item.itemId,

here the same too, i delete fast dail , install new the 3.5.1 no running

i installed the fast_dial-3.5.1-fx-modified.xpi , not running

i can open with crtl +t the fast dail page, but there ist nothing

Mmmm

This is most interesting.

I guess the most simple check would be to see if your settings in Firefox have been changed.
You know whether Firefox is set to open in about:blank or not and whether your home page has been changed
Maybe this setting was changed without your knowledge.
This does happen

If as you say all your bookmarks are still in the Fast Dial folder in bookmarks it suggests that your bookmarks have not been corrupted.
This is a good sign if true.

The only other thing that you could try is to remake Fast Dial as Home
This used to be possible before when with a right click on bookmarks in the context menu, there was the option to make Fast Dial home.
It would be good (if possible) to do that on your Fast Dial Folder in Bookmarks

That is all that comes to mind right now...