Trouble upgrading 10.7.4 to 10.7.5

I tried using Software Update but got a message saying, "The update "Mac OS X Update" can't be saved. The update could not be verified. It may have been corrupted or tampered with during downloading, The update will be downloaded and checked again the next time that Software Update runs." I've tried it several times, receiving the same message each time, even after using Disk Utilities to verify and repair permissions and also verify the hard drive. Any ideas how to download/install 10.7.5? Thank you.
-Bob