Radeon 7500 warning message + Blender issues

[Shobaki sam.]

Hello group,

Here is my first problem, as explained in PR http://www.freebsd.org/cgi/query-pr.cgi?pr=59298:
When trying to render any scene with blender, and pushing the "render" button, blender core dumps with this
error message:
-------------------------
assertion "vb.context == ctx" failed: file "radeon_vtxfmt.c", line 1061
Abort trap (core dumped)
-------------------------
I tried to set RADEON_NO_VTXFMT to 1 but the problem go somewhere else, blender becomes very unstable and crash too frequently.

My other problem is about a strange warning message i got in Xfree86 logs as explained in http://www.freebsd.org/cgi/query-pr.cgi?pr=59297 :
when closing any opengl window application with the escape key, described in this sample code:
----------------------
if(key == ESCAPE)
    {
      glutDestroyWindow(window);
     exit(0);
    }
----------------------
i got this warning in /var/log/XFree86.0.log:
----------------------
(WW) RADEON(0): [dri] RADEONDRITransitionTo2d: kernel failed to unflip buffers.
----------------------
But if i use the system close button, everything is going fine, but is this error is harmless or not ?

Thanks for any help.

Sam._