You can use any root file manager...........i'm using root explorer.
Steps for backing up modules......
1. in root explorer go to system/lib/ directory.
2. there u will see the folder which is namely as a modules.
3. just copy this module folder to your desired location. (i suggest to ext. card)
4. n place these modules at any safe place for future use.......like in pc.
Steps for restoring modules........
1. place modules to the ext. card or download from the attachment.
2. now open root explorer, n copy modules folder.
3. then browse to system/lib folder.
4. n paste the modules folder here....... (it will ask to replace select yes)
5. then set permission - rwxr-xr-x of folder.
6. reboot! done.
If You don't have the backup of modules, just download modules from the attachment.