Stopped tracking

Have been using piwik for a client’s website (www.avescosmetics.com) which was working until 5th June, when all tracking stopped. It doesn’t show any visitors anymore.

I have tried calling
www.avescosmetics.com/piwik/piwik.php?idsite=1
although this doesn’t register a visit.

I was running 1.4 when this started, have updated to 1.5 and no change (still doesn’t work).

Can anyone help?

can you see any error in your webserver error log?