NowI co'uldn't update or install any packages, and also couldn't reinstall or fix the issues about RPM. 
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[root@taff]# yum  cleanall
Loaded plugins: refresh-packagekit
rpmdb: /var/lib/rpm/Packages: unsupported hash version: 9
error: cannot open Packages index using db3 - Invalid argument (22)
error: cannot open Packages database in /var/lib/rpm
Traceback (most recent call last):
  File "/usr/bin/yum", line 29, in <module>
    yummain.user_main(sys.argv[1:], exit_code=True)
  File "/usr/share/yum-cli/yummain.py", line 229, in user_main
    errcode = main(args)
  File "/usr/share/yum-cli/yummain.py", line 84, in main
    base.getOptionsConfig(args)
  File "/usr/share/yum-cli/cli.py", line 184, in getOptionsConfig
    enabled_plugins=self.optparser._splitArg(opts.enableplugins))
  File "/usr/lib/python2.5/site-packages/yum/__init__.py", line 192, in _getConfig
    self._conf = config.readMainConfig(startupconf)
  File "/usr/lib/python2.5/site-packages/yum/config.py", line 758, in readMainConfig
    yumvars['releasever'] = _getsysver(startupconf.installroot, startupconf.distroverpkg)
  File "/usr/lib/python2.5/site-packages/yum/config.py", line 828, in _getsysver
    idx = ts.dbMatch('provides', distroverpkg)
TypeError: rpmdb open failed
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[root@taff download]# rpm -ivh rpm-build-4.7.1-1.fc11.i586.rpm 
rpmdb: Program version 4.7 doesn't match environment version 4.5
error: db4 error(-30971) from dbenv->open: DB_VERSION_MISMATCH: Database environment version mismatch
error: cannot open Packages index using db3 -  (-30971)
error: cannot open Packages database in /var/lib/rpm
warning: rpm-build-4.7.1-1.fc11.i586.rpm: Header V3 RSA/SHA256 signature: NOKEY, key ID d22e77f2
rpmdb: Program version 4.7 doesn't match environment version 4.5
error: db4 error(-30971) from dbenv->open: DB_VERSION_MISMATCH: Database environment version mismatch
error: cannot open Packages database in /var/lib/rpm
--------------------------------------------------------
  

I think those problems are terrible:

rpmdb: Program version 4.7 doesn't match environment version 4.5
rpmdb: /var/lib/rpm/Packages: unsupported hash version: 9
error: cannot open Packages index using db3 - Invalid argument (22)

Is there any friends meet this problem? Pls help to fix them. Thanks so much!