rewire unstable?

hello

i am using Logic 6.3.1 with Max MSP via rewire. when it works ,this is a nice setup. however i find it very unstable, with rewire losing the connection evry 20 minutes or so, so i have to re select rewire as a driver, or restart either or both apps. also both apps will randomly quit for no obvious reason every 45 minutes or so. does anyone with experience of running a setup like this, have any tips for keeping it running smoothly?

j