I am having the same crashing problems. It seems to crash while using pretty much anything that changes somethings shape, and crashes very often.
Sketchup Make 15.3.331 64-bit
Extensions - AMS Soften Edges, Taper Maker, PathCopy, SuSolid, Soap Skin.
Computer:
Dell Inc. Studio XPS 8100
2.93 gigahertz Intel Core i7 870
8152 Megabytes Usable Installed Memory
ATI Radeon HD 5700 Series Video Card
Windows 7 Home Premium (x64) Service Pack 1 (build 7601)