New Post: Sporadic "Uncaught exception 'Exception' with message 'Could not close zip file "

Thanks Mark - your point about 'Invalid Directory Paths' made me convert the relative paths that I had been using to absolute paths and for now that seems to have fixed it.

So for any relative php newbies I was using this to save:

$xlsPath = '../data/' . PRODUCT . '/' . $client . '/output/'.session_id().'/';

$objWriter->save($xlsPath.$xlsFilename);

now I'm using:

$xlsPath = $_SERVER['DOCUMENT_ROOT']."/QA/RIG/data/" . PRODUCT ."/". $client . '/output/'.session_id().'/';

$objWriter->save($xlsPath.$xlsFilename);

So far this seems to have worked, will post here again if the error re-occurs.