I think that I ran into this today while working on the X1900XT on Windows, so
it appears to be a potentially general issue. Some notes:
1) It occurs in both the ARB and GLSL backends.
2) The GL_INVALID_OPERATION is actually triggered by drawing, it is simply be
"caught" by the next Sh GL function to be called. That means that it could be
caused by anything from improperly setup state to incorrectly bound textures, etc.
3) Using a single texture (either kd or ks) avoids the problem...
4) Mipmapping or not doesn't seem to matter.

Let's fix this for the final release of 0.8.

I can reproduce the problem on my X300 as well.

Lean Fuglsang (lean at omnia dot dk) reported the following problem on an ATI
9700 card:
When I try to run the texture example from libsh 0.8rc0, I get a black
window with some help text.
The console reports:
GlBackend.cpp:133: GL ERROR on ArbCode.cpp: 373: GL_INVALID_OPERATION
GlBackend.cpp:134: GL ERROR call: glDisable(GL_VERTEX_PROGRAM_ARB)
The result of "fglrxinfo":
display: :0.0  screen: 0
OpenGL vendor string: ATI Technologies Inc.
OpenGL renderer string: MOBILITY RADEON 9700 Generic
OpenGL version string: 1.3.5272 (X4.3.0-8.16.20)