Export not working

For some reason the export function has stopped working. I take regular backups but would like to use the export now before upgrading WordPress. It has worked before, but now all I get is an error message saying ‘Error!’. That’s it – no explanation, nothing happens, just a blank white page and the error text on the top left corner.
I’m using Ask Apache Password manager, could that be causing the problem? It has worked before with Ask Apache installed though…