OpenGL signaled (1280 . iNVLID-ENUM) from GET-INTGER-VI have two users for whom a call to (gl:get-integer :num-extensions) errors with:
The only thing they both have in common it seems is OSX
It seems from here https://developer.apple.com/library/mac/releasenotes/general/macosxlionapidiffs/OpenGL.html that this enum was only added in OsX 10.7 (Lion) but at least one of these folks is using mavericks which has 4.2 support (so I'm told :))