MM freezing when asking friends for objects or help with fights

Does anybody know what settings I need to change (and how) in order to stop the game from freezing/crashing every time I ask friends for objects or to participate in a fight? It works fine on my work computer, but not on the one at home (this problem has recently occured, it didn't use to be like that).

Grateful for any tips!

What're u using at home? If windows, well enuf said. Windows never works well. I play on an iPad, and rarely have a problem.