I'd pull my hair out if I had many left to pull.

Ok, just when I thought things we're good regarding pushing app from the BES, I'm now getting "Syntax error in vendorxml line 0, column 0. Reason: XML document must have a top level element"

The vendor.xml file I'm using came from RIM.

Any suggestions?

Thanks

PS I also deleted the app and folder and deleted the config, recreated everything and indexed to make sure the specification.pkg and pkgDBcache.xml were new and still the same error.

Try removing this line from the vendor.xml.
{
<?xml version="1.0"?>
}

Then remove specification.pkg and pkgDBcache.xml and re-index again.