Adobe Export PDF conversion failures - URGENT help required

Hi, after subscribing to and using Adobe Export PDF without any problems for 2+ years now, in the last fortnight suddenly it's not working any more.  Every PDF file I've tried to convert ends with the message 'conversion failure'.  I've tried converting direct from PDF browser on my PC and also through online document cloud - same result.  I've tried using different browsers but no joy whether it's in IE, Firefox or Chrome.  Of note, I've also tried in two different PCs - both at home and at work.  I finally tried online chat with Adobe advisers who, after nearly an hour of going around in circles and passing me on to a supposedly 'technical adviser' who said he couldn't help, eventually told me I should use this forum to post my question/problem.

So please, can ANYONE out there - Adobe expert or otherwise - help me solve this problem as currently my Adobe Export PDF is totally useless and will not convert as it's supposed to.