[racket] gl2d / gl-world: Debugging strange error / determining which libraries are missing

For whatever reason I don't have that directory. I ran this version instead:
https://raw.github.com/plt/racket/master/collects/sgl/examples/gears.rkt

That worked fine, rotating the gears as expected and printing this to
the console:
RENDERER: Mesa DRI Intel(R) 945GM x86/MMX/SSE2
VERSION: 1.4 Mesa 8.0.2
VENDOR: Tungsten Graphics, Inc
EXTENSIONS: ...

If it helps, I'm using Ubuntu 12.04 which either didn't have Racket or
at least not a newer version, so I'm installing from this PPA:
deb http://ppa.launchpad.net/plt/racket/ubuntu precise main

On Thu, May 17, 2012 at 4:58 PM, Michael Wilber <mwilber at uccs.edu> wrote:
> Can you run other OpenGL Racket programs? For example, try the gears example:
>
> racket /usr/lib/racket/collects/sgl/examples/gears.rkt
>
> On Thu, 17 May 2012 17:49:21 -0400, JP Verkamp <racket at jverkamp.com> wrote:
>> Hopefully someone out there can help me out, I've run into a a bit of
>> a problem with the gl2d and gl-world packages from PLaneT. I've got a
>> relatively small sample and whenever I run the code (even after
>> commenting out all of the OpenGL specific code other than the big-bang
>> call), I always get this error:
>>
>> send: target is not an object: #f for method: call-as-current
>>
>> The one relevant response I've found thus far on the subject is from
>> Matthew Flatt from last December on the mailing list (
>> http://lists.racket-lang.org/users/archive/2011-October/048813.html )
>> which says to check "Do you have "libgdkglext-x11-1.0" and
>> "libgtkglext-x11-1.0" installed?", which I do. There's a .so for each
>> in my /usr/lib directory. After that though, I'm not sure where to go.
>> Is there perhaps some way to check which libraries that Racket is
>> trying to load / what else might be causing the error?
>>
>> Thanks,
>> JP
>> ____________________
>>   Racket Users list:
>>   http://lists.racket-lang.org/users