Can't access SEF advance in backend

Morning ..

site is at www.thevillablog.co.uk

I noticed this morning that the URL had changed .. a number getting added, but not in the usual Joomla place ...

so I went into SEF advance at the backend but couldn't get in, so i updated SEF just in case that was it but after that, I'm still not getting in ...

i have recently installed easysocial from stackideas .. but not sure why that would have an impact ..

any suggestions/help??

thanks

Try installing ionCube