Description of problem:
This very well may be triggered by a faulty local mirror, but it really shouldn't crash the installer.

Version-Release number of selected component:
anaconda-20.25.15-1

The following was filed automatically by anaconda:
anaconda 20.25.15-1 exception report
Traceback (most recent call first):
  File "/usr/lib/python2.7/site-packages/yum/yumRepo.py", line 1026, in _getFile
    raise Errors.NoMoreMirrorsRepoError(errstr, errors)
  File "/usr/lib/python2.7/site-packages/yum/yumRepo.py", line 1842, in _retrieveMD
    **kwargs)
  File "/usr/lib/python2.7/site-packages/yum/yumRepo.py", line 234, in populate
    db_fn = repo._retrieveMD(mydbtype)
  File "/usr/lib/python2.7/site-packages/yum/sqlitesack.py", line 934, in searchFiles
    self.populate(repo, mdtype='filelists')
  File "/usr/lib/python2.7/site-packages/yum/sqlitesack.py", line 46, in newFunc
    return func(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/yum/sqlitesack.py", line 1256, in _search
    for pkg in self.searchFiles(name, strict=True):
  File "/usr/lib/python2.7/site-packages/yum/sqlitesack.py", line 46, in newFunc
    return func(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/yum/sqlitesack.py", line 1270, in getProvides
    return self._search("provides", name, flags, version)
  File "/usr/lib/python2.7/site-packages/yum/packageSack.py", line 610, in _computeAggregateDictResult
    sackResult = apply(method, args)
  File "/usr/lib/python2.7/site-packages/yum/packageSack.py", line 410, in getProvides
    return self._computeAggregateDictResult("getProvides", name, flags, version)
  File "/usr/lib/python2.7/site-packages/yum/transactioninfo.py", line 603, in getNewProvides
    for pkg, hits in self.pkgSack.getProvides(name, flag, version).iteritems():
  File "/usr/lib/python2.7/site-packages/yum/transactioninfo.py", line 624, in getProvides
    result.update(self.getNewProvides(name, flag, version))
  File "/usr/lib/python2.7/site-packages/yum/depsolve.py", line 1071, in _checkInstall
    provs = self.tsInfo.getProvides(*req)
  File "/usr/lib/python2.7/site-packages/yum/depsolve.py", line 993, in _resolveRequires
    thisneeds = self._checkInstall(txmbr)
  File "/usr/lib/python2.7/site-packages/yum/depsolve.py", line 877, in resolveDeps
    CheckDeps, checkinstalls, checkremoves, missing = self._resolveRequires(errors)
  File "/usr/lib/python2.7/site-packages/yum/__init__.py", line 1173, in buildTransaction
    (rescode, restring) = self.resolveDeps()
  File "/usr/lib64/python2.7/site-packages/pyanaconda/packaging/yumpayload.py", line 1282, in checkSoftwareSelection
    (code, msgs) = self._yum.buildTransaction(unfinished_transactions_check=False)
  File "/usr/lib64/python2.7/site-packages/pyanaconda/packaging/yumpayload.py", line 1359, in preInstall
    self.checkSoftwareSelection()
  File "/usr/lib64/python2.7/site-packages/pyanaconda/install.py", line 161, in doInstall
    payload.preInstall(packages=packages, groups=payload.languageGroups())
  File "/usr/lib64/python2.7/threading.py", line 764, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/usr/lib64/python2.7/site-packages/pyanaconda/threads.py", line 192, in run
    threading.Thread.run(self, *args, **kwargs)
NoMoreMirrorsRepoError: failure: repodata/be8d0a1b4330948e35eac07b755b2ea027cac583b29ca0d4c44ceec2a0345584-filelists.sqlite.bz2 from fedora-20-updates-testing-x86_64: [Errno 256] No more mirrors to try.
http://fedora.cora.nwra.com/updates/testing/20/x86_64/repodata/be8d0a1b4330948e35eac07b755b2ea027cac583b29ca0d4c44ceec2a0345584-filelists.sqlite.bz2: [Errno 14] HTTP Error 404 - Not Found

Additional info:
cmdline:        /usr/bin/python  /sbin/anaconda
cmdline_file:   BOOT_IMAGE=/images/pxeboot/vmlinuz inst.stage2=hd:LABEL=Fedora\x2020\x20x86_64 ks=http://ks.cora.nwra.com/system/pacas
executable:     /sbin/anaconda
hashmarkername: anaconda
kernel:         3.11.10-301.fc20.x86_64
product:        Fedora
release:        Cannot get release name.
type:           anaconda
version:        20