Then it's most likely just the video player flash executable (swf file) that's not correctly handled by IE. Instead of executing it it's handled as downloadable file. Do you have the flash plugin installed in IE? If yes, the problem is likely caused by the way the video is embedded in the page by the Videos plugin (oftenly IE needs such kind of things handled differently than any other browser). If the flash plugin is not installed in IE, install it and try again.
The CSV exporter plugin should allow you to do that. It's only available for Elgg 1.9 or newer here on the community site (https://elgg.org/plugins/1939447) but there's a version for 1.8 available at https://github.com/ColdTrick/csv_exporter/releases/tag/v1.0.
But you might first set up the cronjobs again on your new server as you mentioned that cronjobs no longer work (https://elgg.org/discussion/view/2630047/garbage-collector-15#elgg-object-2630262) and the newsletter plugin might also need a cronjob to work.
That's an error from the MySQL server due to the max allowed concurrent connections being set too low for your site to properly work. You would have to increase the value of max_connections in the MySQL server config my.cnf. You might also want to set a value for wait_timeout if not already set or decrease the value if set. The wait_timeout value is the time in seconds the server waits before closing an unused connection. Default is 28800 seconds (8 hours) which means that it might not be ablue to open a new connection (due to the limit of 15 set for max_connections) even if there are less users on your site. Setting wait_timeout = 600 works for me.
Increasing max_connections will result in more memory being used by the MySQL server. So, be careful with increasing.
If you are on a shared server with no permission to alter my.cnf of the MySQL server, you would have to get in contact with the support to ask for help. If they don't allow more than 15 connections you might need to change your hosting plan or hoster.
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