mac mail crash on preview

[nadvys]

When opening an attachment i have regular crash of either mail or preview with following crash report:
rocess: Preview 2715
Path: /Applications/Preview.app/Contents/MacOS/Preview
Identifier: com.apple.Preview
Version: 5.0.1 (503)
Build Info: Preview-5030000~4
Code Type: X86-64 (Native)
Parent Process: launchd 110

Date/Time: 2010-03-08 15:08:29.480 +0100
OS Version: Mac OS X 10.6.2 (10C540)
Report Version: 6

Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000018
Crashed Thread: 0 Dispatch queue: com.apple.main-thread

Application Specific Information:
objc_msgSend() selector name: isEqualToString:
Thread 0 Crashed: Dispatch queue: com.apple.main-thread
0 libobjc.A.dylib 0x00007fff8195f2c4 objc_msgSend_vtable11 + 12
1 com.apple.AppKit 0x00007fff81e845dd ConvertOutgoingValueForAttribute + 48
2 com.apple.AppKit 0x00007fff81e84786 CopyAppKitUIElementAttributeValueNoCatch + 104
3 com.apple.AppKit 0x00007fff81e84b61 CopyAttributeValue + 343
4 com.apple.HIServices 0x00007fff88a031e5 _AXXMIGCopyAttributeValue + 266
5 com.apple.HIServices 0x00007fff88a0dfbd _XCopyAttributeValue + 411
6 com.apple.HIServices 0x00007fff889ea365 mshMIGPerform + 460
7 com.apple.CoreFoundation 0x00007fff874df551 __CFRunLoopRun + 5201
8 com.apple.CoreFoundation 0x00007fff874ddc2f CFRunLoopRunSpecific + 575
9 com.apple.HIToolbox 0x00007fff80b15a4e RunCurrentEventLoopInMode + 333
10 com.apple.HIToolbox 0x00007fff80b15853 ReceiveNextEventCommon + 310
11 com.apple.HIToolbox 0x00007fff80b1570c BlockUntilNextEventMatchingListInMode + 59
12 com.apple.AppKit 0x00007fff81c381f2 _DPSNextEvent + 708
13 com.apple.AppKit 0x00007fff81c37b41 -NSApplication nextEventMatchingMask:untilDate:inMode:dequeue: + 155
14 com.apple.AppKit 0x00007fff81bfd747 -NSApplication run + 395
15 com.apple.AppKit 0x00007fff81bf6468 NSApplicationMain + 364
16 com.apple.Preview 0x0000000100001644 start + 52

OR

Process: Mail 7639
Path: /Applications/Mail.app/Contents/MacOS/Mail
Identifier: com.apple.mail
Version: 4.2 (1077)
Build Info: Mail-10770000~4
Code Type: X86-64 (Native)
Parent Process: launchd 98

Date/Time: 2010-03-08 12:05:23.834 +0100
OS Version: Mac OS X 10.6.2 (10C540)
Report Version: 6

Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000018
Crashed Thread: 0 Dispatch queue: com.apple.main-thread

Application Specific Information:
objc_msgSend() selector name: isEqualToString:

Thread 0 Crashed: Dispatch queue: com.apple.main-thread
0 libobjc.A.dylib 0x00007fff8195f2c4 objc_msgSend_vtable11 + 12
1 com.apple.AppKit 0x00007fff81e845dd ConvertOutgoingValueForAttribute + 48
2 com.apple.AppKit 0x00007fff81e84786 CopyAppKitUIElementAttributeValueNoCatch + 104
3 com.apple.AppKit 0x00007fff81e84b61 CopyAttributeValue + 343
4 com.apple.HIServices 0x00007fff88a031e5 _AXXMIGCopyAttributeValue + 266
5 com.apple.HIServices 0x00007fff88a0dfbd _XCopyAttributeValue + 411
6 com.apple.HIServices 0x00007fff889ea365 mshMIGPerform + 460
7 com.apple.CoreFoundation 0x00007fff874df551 __CFRunLoopRun + 5201
8 com.apple.CoreFoundation 0x00007fff874ddc2f CFRunLoopRunSpecific + 575
9 com.apple.HIToolbox 0x00007fff80b15a4e RunCurrentEventLoopInMode + 333
10 com.apple.HIToolbox 0x00007fff80b15853 ReceiveNextEventCommon + 310
11 com.apple.HIToolbox 0x00007fff80b1570c BlockUntilNextEventMatchingListInMode + 59
12 com.apple.AppKit 0x00007fff81c381f2 _DPSNextEvent + 708
13 com.apple.AppKit 0x00007fff81c37b41 -NSApplication nextEventMatchingMask:untilDate:inMode:dequeue: + 155
14 com.apple.AppKit 0x00007fff81bfd747 -NSApplication run + 395
15 com.apple.AppKit 0x00007fff81bf6468 NSApplicationMain + 364
16 com.apple.mail 0x0000000100002150 0x100000000 + 8528


i did a HD check and permission repair but to no avail.
I have the same problem on 2 computers running latest 10.6.2
any ideas? Thanks for any help already