I also had the same problem on an HP Compaq NX6110. 
Standby and Hibernation fails. 
Kernel points out to update IPW2200 driver. I found this on /var/log/messages.

I use Edgy, Kernel Ver: 2.6.17-11-386


Apr  7 09:38:51 karo gnome-power-manager: (ozubu) Suspending computer because user clicked suspend from tray menu
Apr  7 09:38:59 karo kernel: [17213620.968000] ACPI: PCI interrupt for device 0000:02:0e.0 disabled
Apr  7 09:38:59 karo kernel: [17213621.040000] ACPI: PCI interrupt for device 0000:02:04.0 disabled
Apr  7 09:39:02 karo kernel: [17213623.416000] Stopping tasks: ========================================================================================================================================|
Apr  7 09:39:02 karo kernel: [17213623.868000] Restarting tasks... done
Apr  7 09:39:03 karo kernel: [17213624.636000] b44.c:v1.00 (Apr 7, 2006)
Apr  7 09:39:03 karo kernel: [17213624.636000] ACPI: PCI Interrupt 0000:02:0e.0[A] -> GSI 16 (level, low) -> IRQ 185
Apr  7 09:39:03 karo kernel: [17213624.644000] eth0: Broadcom 4400 10/100BaseT Ethernet 00:12:79:bb:fa:b5
Apr  7 09:39:03 karo kernel: [17213624.824000] ieee80211: 802.11 data/management/control stack, git-1.1.13
Apr  7 09:39:03 karo kernel: [17213624.824000] ieee80211: Copyright (C) 2004-2005 Intel Corporation <email address hidden>
Apr  7 09:39:03 karo kernel: [17213624.844000] ipw2200: Intel(R) PRO/Wireless 2200/2915 Network Driver, 1.1.2kmprq
Apr  7 09:39:03 karo kernel: [17213624.844000] ipw2200: Copyright(c) 2003-2006 Intel Corporation
Apr  7 09:39:03 karo kernel: [17213624.844000] Driver 'ipw2200' needs updating - please use bus_type methods
Apr  7 09:39:03 karo kernel: [17213624.848000] ACPI: PCI Interrupt 0000:02:04.0[A] -> GSI 21 (level, low) -> IRQ 217
Apr  7 09:39:03 karo kernel: [17213624.848000] ipw2200: Detected Intel PRO/Wireless 2200BG Network Connection
Apr  7 09:39:03 karo kernel: [17213625.052000] ipw2200: Detected geography ZZR (14 802.11bg channels, 0 802.11a channels)
Apr  7 09:39:03 karo kernel: [17213625.076000] ADDRCONF(NETDEV_UP): eth0: link is not ready
Apr  7 09:39:03 karo kernel: [17213625.108000] eth1: NETDEV_TX_BUSY returned; driver should report queue full via ieee_device->is_queue_full.
Apr  7 09:39:07 karo kernel: [17213627.756000] ACPI: Power Button (FF) [PWRF]
Apr  7 09:39:07 karo kernel: [17213627.756000] ACPI: Sleep Button (CM) [C1E0]
Apr  7 09:39:07 karo kernel: [17213627.756000] ACPI: Lid Switch [C1E1]
Apr  7 09:39:08 karo kernel: [17213628.940000] ACPI: Transitioning device [C253] to D3
Apr  7 09:39:08 karo kernel: [17213628.940000] ACPI: Transitioning device [C253] to D3
Apr  7 09:39:08 karo kernel: [17213628.940000] ACPI: Fan [C253] (off)
Apr  7 09:39:08 karo kernel: [17213628.940000] ACPI: Transitioning device [C254] to D3
Apr  7 09:39:08 karo kernel: [17213628.940000] ACPI: Transitioning device [C254] to D3
Apr  7 09:39:08 karo kernel: [17213628.940000] ACPI: Fan [C254] (off)
Apr  7 09:39:08 karo kernel: [17213628.940000] ACPI: Transitioning device [C255] to D3
Apr  7 09:39:08 karo kernel: [17213628.940000] ACPI: Transitioning device [C255] to D3
Apr  7 09:39:08 karo kernel: [17213628.940000] ACPI: Fan [C255] (off)
Apr  7 09:39:08 karo kernel: [17213628.940000] ACPI: Transitioning device [C256] to D3
Apr  7 09:39:08 karo kernel: [17213628.940000] ACPI: Transitioning device [C256] to D3
Apr  7 09:39:08 karo kernel: [17213628.940000] ACPI: Fan [C256] (off)
Apr  7 09:39:08 karo kernel: [17213628.956000] ACPI: CPU0 (power states: C1[C1] C2[C2] C3[C3])
Apr  7 09:39:08 karo kernel: [17213628.956000] ACPI: Processor [C000] (supports 8 throttling states)
Apr  7 09:39:08 karo kernel: [17213628.968000] ACPI: Thermal Zone [TZ1] (56 C)
Apr  7 09:39:08 karo kernel: [17213628.976000] ACPI: Thermal Zone [TZ2] (39 C)
Apr  7 09:39:08 karo kernel: [17213628.984000] ACPI: Thermal Zone [TZ3] (26 C)
Apr  7 09:39:08 karo kernel: [17213629.060000] ACPI: AC Adapter [C16B] (on-line)
Apr  7 09:39:08 karo kernel: [17213629.112000] ACPI: Battery Slot [C16D] (battery present)
Apr  7 09:39:08 karo kernel: [17213629.112000] ACPI: Battery Slot [C16C] (battery absent)
Apr  7 09:39:13 karo gnome-power-manager: (ozubu) Resuming computer