i cant install any application

[ubuntufan10]

i was download some application , and suddenly my laptop turned off , i forgot to plug it in , anyways i turn it back on , and now i get first and error , it cant mount / or something like that so i press I and ignore anyways i login and everything works , now i am trying to download some application but i get this "Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/aptdaemon/worker.py", line 768, in simulate
    return self._simulate_helper(trans, status_path)
  File "/usr/lib/python2.6/dist-packages/aptdaemon/worker.py", line 936, in _simulate_helper
    return depends, status, self._cache.required_download, \
  File "/usr/lib/python2.6/dist-packages/apt/cache.py", line 218, in required_download
    pm.get_archives(fetcher, self._list, self._records)
SystemError: E:I wasn't able to locate file for the libsdl-perl package. This might mean you need to manually fix this package.
"
how can i fix this ??

thank you