I know this is reaaaaally old thread, but in case someone line me finds themselves here, I did reproduce the exact same behavior as described by xdg (Crashing and then dereferencing work around) on perl v5.10.1 built for MSWin32-x86-multi-thread However freeing a lot of variables (by undef-ing them) before calling perl fixed it. I shouldn't call it "fix" but rather temporarily avoided. Anyone came across any real solutions?