They said that hextech crashes are because of outdated Adobe Air (Which league runs off of) and outdated graphics drivers. Either update those or wait for them to make a fix.
My Hextech works fine. Just recently opened up a skin shard of Star Guardian Lux just a few minutes ago. I'd probable take the advice of updating your drivers/Adobe Air and see if that works. If it works: Great! If not... Uh... Not sure what to say then.