Ho risolto il problema e finalmente yum va! Grazie mille per l'aiuto Andy Caps, non sai quanti problemi mi hai risolto...

PERO'...
Ho provato ad installare mysql-server e dopo un pò di tempo mi da quest'errore:

--> Processing Conflict: python-devel conflicts python< 2.4.1-2
Traceback (most recent call last):
File "/usr/bin/yum", line 8, in ?
yummain.main(sys.argv[1:])
File "/usr/share/yum-cli/yummain.py", line 104, in main
(result, resultmsgs) = base.buildTransaction()
File "/usr/lib/python2.3/site-packages/yum/__init__.py", line 174, in buildTransaction
(rescode, restring) = self.resolveDeps()
File "/usr/lib/python2.3/site-packages/yum/depsolve.py", line 190, in resolveDeps
(checkdep, missing, conflict, errormsgs) = self._processConflict(dep)
File "/usr/lib/python2.3/site-packages/yum/depsolve.py", line 492, in _processConflict
uplist = self.up.getUpdatesList(name=confname)
UnboundLocalError: local variable 'confname' referenced before assignment



Cosa devo andare a modificare???