MyMathLab mathxl flash content broken.

This might as well be a sequel to http://ubuntuforums.org/showthread.php?t=2318193

Urgent this time.

YouTube videos work, but not MML. I tried installing gnash and swfdec to no avail. I just did a reinstall, updating in the process, and it did not help. I'm stumped. I suppose somebody could have replaced my Kanguru's iso image (14.04.2) with a slightly altered one with broken flash, but I don't know what they could have changed (that would have survived the update process). It's been year+ long paranoia here.

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I will try reinstalling the dependencies one by one. Should I try installing the recommended or suggested packages?
list is here http://packages.ubuntu.com/trusty/flashplugin-installer

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I do remove the unconfined execute (Ux) bits form the bottom of the firefox profile before parsering, but the rest is untouched.