If you have got your Hardrive to 100% there is not room for the OS to run 

this will cause rutorrent to crash error 502 

or Bad response from server: (0 [error,getplugins]).

to fix this you can go on via FTP or SSH and delete some content to get under 100% everything will then return to normal you can not get on FTP and do not know how to use SSH you can open a support ticket and we will add a few GB to your slow for a few hours to allow you to clean up