Client Error "Failed to create dumpfile"

i dont know what has been happening but when im in champ select or doing runes my client crashes and a text box pops up failed to create dump file and it makes it were im still in champ select but i cant see and i time out of the q and get penalized ive dine lost about 30 lp becasue of it and have had many dodge timers when i didnt dodge i just want to know how to fix it