I could reproduce this bug only in deferred rendering mode and in some conditions (facing one way in my skybox, I never get a crash, but facing at a 180° angle, I always get crashes...). Not sure why however...
I also tried wire frame mode with deferred rendering active in viewer v3.0.6: I don't get a crash, but wire frame is obviously completely broken (black screen, with only full bright prims appearing as ghostly forms... Spooky !

)... I guess LL didn't really care about what happens when you switch to wire frame mode with deferred rendering active, thus why some bad things happen... A work around would be to disable deferred rendering altogether while wire frame is on, and switch it back on when leaving wire frame mode... It doesn't make much sense to keep deferred rendering on while in wire frame mode anyway, since then shadows have nothing to project on (no surface drawn)...
EDIT: In fact, in v2/3 viewers, toggling wire frame does disable automatically deferred rendering... I implemented the corresponding code and wire frame mode works now just fine with deferred rendering on in the Cool VL Viewer. The fix will be in the next release.