Sorry Mike. Our last replies clashed & I didn't mean to interfere. I'm downloading the campaign right now & I'm sure we can soon fix this between us. The most likely cause is a 3rd party aircraft that is used for the first time in mission Cru5. Find that & we have the culprit.

Here's a few tips for installing campaigns or anything else for that matter.
1. If you're using WinZip make sure you have a current version (WinZip 7.0 or later.). Some AI only aircraft have empty Panel & Sound folders which early versions of WinZip will not extract. All aircraft must have Panel/Sound folders to work, even if they're empty.
2. Make sure the WinZip "Use Folder Names" option is checked.
3. Ignore all instructions to unzip files direct to the sim. Unzip the files to a Temp folder & paste them in manually.
In my experience, these are the cause of most installation problems.