I recently installed Mint 8 and discovered the same problem.

Compaq Presario SR1503WM
Processor _Intel(R) Celeron(R) CPU 2.93GHz
Family, model, stepping _15, 4, 1 (Pentium 4)
Cache Size _256kb
Frequency _2932.99MHz
BogoMIPS_5865.97
Byte Order_Little Endian
Memory_2053MB
Operating System_Linux Mint 8 Helena - Main Edition
intrgrated grapics_Intel 845GV GMCH (Extreme)
OpenGL Renderer_Mesa DRI Intel(R) 845G GEM 20090712 2009Q2 RC3 x86/MMX/SSE2
Audio Adapter_ICH4 - Intel 82801DB-ICH4

Is there some tweeking I can do, or is this a dead horse?

Maybe your card doesn't support compositing?

http://forlong.blogage.de/entries/pages/Compiz-Check

Results...

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... [WARN]

Something potential problematic has been detected with your setup:
Warning: PCI ID 8086:2562 detected.

Would you like to know more? (Y/n) y

Your particular graphics chip may be blacklisted on certain distributions.
However that does not necessarily mean you will not be able to run.

Bummer. It worked on 7.10 and 8.04. I wonder if there's a way extract code and impliment it on 9.10.