Fedora :: System Network Services Not Compatible With This Version

After a recent update of fedora 15 (2 days ago) I lost my networkmanager icon in top panel completely. Then I check network manager version & found it's version 0.8.0.9997-5.git20110702. After this update I can't connect to internet by any means either via wired or wireless connection. When I try to open Network option from system settings it giving me an error: System network services are not compatible with this version.

I also try to open network-connection-editor by pressing Alt+F2 & typing:
nm-connection-editor

But it not works as well, I can't see any existing network connection there, moreover I can't even manually add any type of network connection there including mobile broadband! Then I do some googling from my windows machine & found this thread- [URL]. According to this thread I try to do downgrading of following 3 packages-

Code:
networkmanager
networkmanager-glib
networkmanager-gnome
But I can't downgrade via yumex as there's no internt connection in fedora. so i do a trick of myself. yumex suggests me to downgrade them to previous version 0.8.0.999-2.git20110509
so i manually download those 3 packages from my windows machine & copy them to /var/cache/yum/... folder. After that I do downgrading via yumex. But even after downgrading problem isn't solved. Same things happening still. No networkmanager icon in top panel & no internet
at present, there's no internet connection in my fedora 15 machine & I'm writing this post from my windows machine.

Moreover when I give this command in terminal:
Code:
sudo service network start
it giving me FAILED status.