I just installed Ubuntu 12.04 on my wifes Dell Inspiron 1501, which uses an R300 ATI graphics chip. Neither the Dash or HUD appear when pushing the appropriate key. When I try unity --reset & in the terminal, I see that over and over it's spitting out:

r300: CS space validation failed. (not enough memory?) Skipping rendering.

This is just after starting Ubuntu with no apps open, so I find it hard to believe that just rendering the Dash / HUD is completely blowing out the VRAM. Any suggestions on getting this working?

/usr/lib/nux/unity_support_test -p 

shows

OpenGL vendor string: X.Org R300 
Project OpenGL renderer string: Gallium 0.4 on ATI RS480 
OpenGL version string: 2.1 Mesa 8.0.2 
Not software rendered: yes
Not blacklisted: yes
GLX fbconfig: yes
GLX texture from pixmap: yes
GL npot or rect textures: yes
GL vertex program: yes
GL fragment program: yes
GL vertex buffer object: yes
GL framebuffer object: yes
GL version is 1.4+: yes

Unity 3D supported: yes

All sections say "YES"