I solve the similar problem on my Z61m two month ago. If You use framebuffer, try remove it. So, if You have in menu.lst (grub) or lilo.conf (lilo) line with vga=7xx then set vga=0 or remove this settings. Reboot and try suspend to RAM again.
I hope, that this helps You.
Here is my pm-suspend.log:
Mon Aug 27 20:26:37 EDT 2007: running suspend hooks.
===== Mon Aug 27 20:26:37 EDT 2007: running hook: /usr/lib/pm-utils/sleep.d/00clear =====
===== Mon Aug 27 20:26:37 EDT 2007: running hook: /usr/lib/pm-utils/sleep.d/01grub =====
===== Mon Aug 27 20:26:37 EDT 2007: running hook: /usr/lib/pm-utils/sleep.d/05led =====
===== Mon Aug 27 20:26:37 EDT 2007: running hook: /usr/lib/pm-utils/sleep.d/10NetworkManager =====
===== Mon Aug 27 20:26:37 EDT 2007: running hook: /usr/lib/pm-utils/sleep.d/20video =====
kernel.acpi_video_flags = 3
===== Mon Aug 27 20:26:37 EDT 2007: running hook: /usr/lib/pm-utils/sleep.d/49bluetooth =====
===== Mon Aug 27 20:26:37 EDT 2007: running hook: /usr/lib/pm-utils/sleep.d/50modules =====
===== Mon Aug 27 20:26:37 EDT 2007: running hook: /usr/lib/pm-utils/sleep.d/55battery =====
===== Mon Aug 27 20:26:37 EDT 2007: running hook: /usr/lib/pm-utils/sleep.d/60sysfont =====
===== Mon Aug 27 20:26:37 EDT 2007: running hook: /usr/lib/pm-utils/sleep.d/65alsa =====
===== Mon Aug 27 20:26:37 EDT 2007: running hook: /usr/lib/pm-utils/sleep.d/90clock =====
===== Mon Aug 27 20:26:38 EDT 2007: running hook: /usr/lib/pm-utils/sleep.d/94cpufreq =====
===== Mon Aug 27 20:26:38 EDT 2007: running hook: /usr/lib/pm-utils/sleep.d/95led =====
===== Mon Aug 27 20:26:38 EDT 2007: running hook: /usr/lib/pm-utils/sleep.d/99video =====
Mon Aug 27 20:26:38 EDT 2007: done running suspend hooks.