Regarding glew 1.7.0 (and maybe earlier versions??):
The code that does the GetProcAddress lookup for glDrawArraysInstancedARB and glDrawElementsInstancedARB is misplaced in the _glewInit_GL_ARB_instanced_arrays() function.
So if GL_ARB_instanced_arrays is not supported by the GL, the glDrawArrays/ElementsARB function pointers are never initialized and
we crash when trying to call them.
The attached patch fixes the glew.c file which we have in piglit. You can easily adapt it for your glew tree. Is there a generator script for this file?