First of all, thank you for supportive comments. I appreciate that you
use QuesoGLC for your application.

About your first issue, can you be more specific when you are speaking
about 64 bits ? What is your OS ? What are your gfx drivers ? What does
configure reports when checking for TLS ?
Can you locate with gdb the exact place where the issue occurs ? (I
suggest to compile QuesoGLC in debug mode. In order to do that, I
suggest to use "./configure --disable-shared CFLAGS="-g -Wall
-DDEBUGMODE" without the double quotes as usual.)
On my side, I am using Ubuntu 7.10 64 bits on an AMD Athlon64 with a gfx
card NVidia GeForce 6800 and I never encountered this issue. Hopefully,
if you give additional informations, I could help you...

Concerning the second issue, you can force QuesoGLC not to use display
lists internally by calling glcDisable(GLC_GL_OBJECTS);
However, it should not change things very much, since QuesoGLC already
detects when glcRender* functions are called within display lists and
deactivates internal display lists whenever it happens.
Finally, I am not sure to understand what is your concern about slowing
things down and what you are meaning with "some caching apart display
lists".