I can't install Mac Os X Update combined 10.6.8

Good.

All indications were that your download process was flawed (and when the update I downloaded yesterday successfully created an install package and that launched the install process up to the point where it told me it couldn't install on a 10.5 OS I was positive).

So does that mean you can install 10.8?

Ok, I am trying to update iWork software and a few other Apple updates in most recent version of Mac Lion on MacBook Pro. I have tried to update 7 or 8 times using the Mac Software Update tool, but everytime it fails and I get this same message regarding "None of the selected updates could be installed. The update could not be expanded and may have been corrupted during download..." etc.

It appears to download all of the software and then towards the end of the update process it says "cleaning" and then it's fails and I get this same message that was mentioned in the original post. I have high speed broadband connection with speeds of 38 download and 12 upload. Everything that uses the Internet connection on my wifi router and modem appear to be working fine.

I don't have another router and I have used this same router many times to update my Mac. Can I go ahead and update to Mountain Lion first and then try these updates again after? If not what else can I try?

1. Have you launched Software Update tool to see what is available and then individually download each update from the Apple web site yourself and then appy them?

2. If the the problem with your SW Update is with your download process, chances are there might be a glitch when downloading ML. I suggest that you try what I suggested above first to verify that your downloads are OK. That said, if the updates apply only to applications other than system SW, you shouldn't have a problem upgrading to ML IF your download process is functioning well.

Good luck and share with us what happens.

I have found that some dmg files that show invalid checksum in 10.6.8 will open just fine in 10.7.5.