After updating the iPad 2 software to 8.2, I can no longer view my mp4 video or music files

Question

Before updating the iOS to 8.2, I had video files and music files on my iPad that I could see listed in playlists in the Music app or in the "Movie" list on the video app.  After the update, I'm not able to see these files to play them.  I can see the files in iTunes but I am not able to play them through iTunes either.  An exclamation point icon appears but it doesn't say anywhere what this icon is representing.  The music files are MP4 audiobooks that I borrow from the library through the Overdrive app and never had any issues with this before I updated the iOS.  The video files are videos on my iMac that I would like to be able to access on the iPad when I travel; they are not items that I purchased through iTunes, which I'm wondering if this makes a difference.  Can I "fix" the apps so that I'm able to once again access my files or is Apply no longer allowing non-iTunes purchases to be viewed or watched on the iPad?  The video files are listed as being "Movies" but they are not visible in the movies list anymore.

Answer 1

Merely clicking the Preview icon in the Dock doesn't cause it to open anything, unless you had one or more windows open the last time it quit.
If you're sure you've installed the latest version of Flash, take each of the following steps that you haven't already tried. After each step, relaunch Safari and test.
1. If you're getting a "blocked plug-in" error, triple-click the line below to select it:
/Library/Internet Plug-Ins Right-click or control-click the highlighted text and select
Services ▹ Open
from the contextual menu. A folder should open. If there is more than one item in the folder with the words "Flash Player" (not "flashplayer") in the name, open the respective Info windows, check the version numbers, and delete all except the latest. You may be prompted for your login password. If you get the same error after doing that, re-download and reinstall Flash. Download it from this page:
Adobe - Install Adobe Flash Player
Never download a Flash update from anywhere else.
2. If you get a "missing plug-in" error, select
Safari ▹ Preferences... ▹ Security
from the Safari menu bar and check the box marked Enable plug-ins.
3. Select
Safari ▹ Preferences... ▹ Extensions
from the Safari menu bar. If any extensions are installed, disable them.
4. In the Safari preference window, select
Privacy ▹ Remove All Website Data
Close the window. Then select
 ▹ System Preferences… ▹ Flash Player ▹ Advanced
and click Delete All. Close the preference pane.