Quote:but most of the toubleshooting links I come to are 404 missing.
The troubleshooting has been restructured a while ago so this might happen. You should take the time to look at our user guide directly.
But sorry, the flowplayer3 plugin has been abandoned with Zenphoto 1.4.5 and is not supported or maintained anymore.
jPlayer should work with 1.4.4 as it is even included. It has nothing to do with PHP5 or newer. If it doesn't I have to recommend upgrading. We cannot really support older Zenphoto releases.
Quicktime is not a supported video container format by any of the players anyway so if you see that icon you probably don't have the video-class plugin and no player plugin enabled. Also please see the error logs. Please see the bug report guidelines:
http://www.zenphoto.org/news/general-contributor-guidelines#reporting-bug
If a video does not work that can have several reasons. jPlayer plays in HTML5 natively on certain browsers and with a flash fallback on some others and especially older ones. (jplayer.org has a table with what browser supports what natively).
Generally all these players don't always play all codecs or codec settings (respectively flash does not)
Regarding videothumbs:
If you have a video files and an image of the same name it is associated as that the purpose of an videothumb. If the video is not recognized the image is not used naturally. If the image has a different naming or letter case (servers are case sensitive, your desktop system is not!) it is recognized as a normal image.