Currently Being ModeratedDec 10, 2012 1:36 AM (in response to travelingG)
Try deleting the com.apple.iwork.pagess.plist located in HD > Users > (your account) > Library > Preferences.
If you are using Lion or Mountain Lion, you can access the User Library folder from the Go menu in Finder while holding down the Option key.
This sometimes clears that SFCompatibility error.
Currently Being ModeratedDec 10, 2012 11:58 AM (in response to fruhulda)
I did Software Update after installing all my programs, and then I also used your link to update, but it didn't seem to have any impact on the problem. Any other ideas?
Currently Being ModeratedDec 10, 2012 3:46 PM (in response to travelingG)
Jerrold Green1, I am using Snow Leopard (10.6.8). Should I still delete com.apple.iwork.pagess.plist?
Yes, and use the path I listed. You can confirm if this is necessary before doing it if you wish.
Switch to a different User Account and see how Pages works there. If necessary, go to Users and Groups in System Preferences and create a new, auxilliary, admin account for testing purposes.
Currently Being ModeratedDec 10, 2012 11:18 PM (in response to fruhulda)
OK, I did this, and Pages still doesn't open. This time the report says:
Process: Pages  Path: /Applications/iWork '09/Pages.app/Contents/MacOS/Pages Identifier: com.apple.iWork.Pages Version: ??? (???) Build Info: Pages-8290000~1 Code Type: X86 (Native)
Parent Process: launchd 
Date/Time: 2012-12-11 07:05:42.513 +0000 OS Version: Mac OS X 10.6.8 (10K549)
Report Version: 6
Interval Since Last Report: 632994 sec Crashes Since Last Report: 16
Per-App Crashes Since Last Report: 11
Anonymous UUID: 39E2D0B7-95B8-433E-A50B-8070BC9FF2F9
Exception Type: EXC_BREAKPOINT (SIGTRAP)
Exception Codes: 0x0000000000000002, 0x0000000000000000
Crashed Thread: 0
Dyld Error Message:
Library not loaded: @rpath/Inventor.framework/Versions/C/Inventor
Referenced from: /Library/Application Support/iWork '09/Frameworks/SFCompatibility.framework/Versions/A/SFCompatibility
Reason: image not found
0x8fe00000 - 0x8fe4163b dyld 132.1 (???) <4CDE4F04-0DD6-224E-ACE5-3C06E169A801> /usr/lib/dyld
Model: iMac9,1, BootROM IM91.008D.B08, 2 processors, Intel Core 2 Duo, 2.66 GHz, 4 GB, SMC 1.37f3
Graphics: NVIDIA GeForce 9400, NVIDIA GeForce 9400, PCI, 256 MB
Memory Module: global_name
AirPort: spairport_wireless_card_type_airport_extreme (0x14E4, 0x8E), Broadcom BCM43xx 1.0 (184.108.40.206.4)
Bluetooth: Version 2.4.5f3, 2 service, 19 devices, 0 incoming serial ports
Network Service: AirPort, AirPort, en1
Serial ATA Device: WDC WD1002FAEX-00Z3A0, 931.51 GB
Serial ATA Device: OPTIARC DVD RW AD-5670S
USB Device: Built-in iSight, 0x05ac (Apple Inc.), 0x8502, 0x24400000 / 3
USB Device: Keyboard Hub, 0x05ac (Apple Inc.), 0x1005, 0x24300000 / 2
USB Device: Apple Optical USB Mouse, 0x05ac (Apple Inc.), 0x0304, 0x24310000 / 5
USB Device: Apple Keyboard, 0x05ac (Apple Inc.), 0x021d, 0x24320000 / 4
USB Device: BRCM2046 Hub, 0x0a5c (Broadcom Corp.), 0x4500, 0x06100000 / 2
USB Device: Bluetooth USB Host Controller, 0x05ac (Apple Inc.), 0x8215, 0x06110000 / 4
USB Device: IR Receiver, 0x05ac (Apple Inc.), 0x8242, 0x04500000 / 2
FireWire Device: FreeAgent FW, Seagate, Up to 800 Mb/sec
Currently Being ModeratedDec 11, 2012 6:30 AM (in response to travelingG)
Pages does not open even when I start from a different user account.
That rules out any plist file problem in the main User account. So the problem seems to be isolated to one of the System Library files or the app itself, or some problem with the OS. Grasping at straws here, but here are some other things to try, assuming that you have the original media for installing iWork:
Use OnyX to purge caches and repair permissions for a general maintenance of your system.
Use Yvan Koenig's iWork '09 uninstaller script to wipe all traces of iWork and it's ancilliary files from your system. Find it on this page.