In the FTB Direwolf 20 pack v3 1.4.6 the game freeze and stop

hello,
games in the FTB Direwolf 20 pack v3 1.4.6
when I run I was part everything is ok but after a few minutes (random)
then I'm in a world mystcraft and then stop the game freeze and crash sends me a file that I attached report for reading.

Thank you I hope to help advance the devellopement your games that I love.

best regards