>>400
compiz-check インスコしました。
結果貼ります

Gathering information about your system...

Distribution: Debian GNU/Linux (6.0.3)
Desktop environment: GNOME
Graphics chip: ATI Technologies Inc Cedar PRO [Radeon HD 5450]
Driver in use: radeon
Rendering method: AIGLX

Checking if it's possible to run Compiz on your system...

Checking for texture_from_pixmap... [ OK ]
Checking for non power of two support... [ OK ]
Checking for composite extension... [ OK ]
Checking for FBConfig... [ OK ]
Checking for hardware/setup problems..../compiz-check: line 491: [: 27071: binary operator expected
[FAIL]

There has been (at least) one error detected with your setup:
Error: Software Rasterizer in use