I found the following on the iPhoneWriter.com website... Thankfully, it worked for me (although it take a little time).
Many people are encountering issues syncing their Music, Movies and/or TV Shows with their iPhone, iPad or iPod Touch. We're happy to report that the iPhoneWriter.Com team has successfully tested the following fix on multiple iDevices.
1) Select the iPhone, iPad or iPod in the iTunes "Devices" section.
2) Drill down into the Music, Movies or TV Shows section that is having issues with greyed out items.
3) Determine the Song(s), Movie(s) or TV Show(s) with the issue.
4) Within the Library in iTunes, drill down into the corresponding Music, Movies or TV Shows section that matches the section with greyed out items.
5) Select the Song(s), Movie(s) or TV Show(s) with the issue.
6) Right-Click selected item(s) and choose the "Get Info" option from the pop-up menu.
7) Select the "Options" tab.
8) Reverse the "Part Of A Compliation" option:
* if the option is currently checked, uncheck it.
* if the option is currently un-checked, check it.
* if the option is currently un-checked and the correspnding drop-down menu
says "No", than check it and select the "Yes" option.
* if the option is currently checked and the correspnding drop-down menu
says "Yes", than check it and select the "No" option.
Finally, after you've addressed all of the greyed out items:
9) Click the "OK" or "Apply" button.
10) Re-Sync your iDevice.
NOTE: For some greyed out items, we had to repeat the steps above multiple times (reversing the setting each time).
While we all utlimately have the same problem, we don't all have the same cause, there are likely several potential solutions for both Mac and Windows users... problem being that no one solution works for everyone's particular situtation.
Hopefully, this will turn out to be something that will work for you.