Safari 5.0 quit unexpectedly

This just started happening a couple of days ago... I don't know what to do to fix it. Your help is appreciated!

Process: Safari [968]

Path: /Applications/Safari.app/Contents/MacOS/Safari

Identifier: com.apple.Safari

Version: 5.0.6 (5533.22.3)

Build Info: WebBrowser-75332203~3

Code Type: X86 (Native)

Parent Process: launchd [639]

Date/Time: 2011-09-26 23:26:39.078 -0500

OS Version: Mac OS X 10.5.8 (9L31a)

Report Version: 6

Anonymous UUID: FCA14146-0E84-443D-861E-E1138443D81C

Exception Type: EXC_BAD_ACCESS (SIGBUS)

Exception Codes: KERN_PROTECTION_FAILURE at 0x00000000006ffff0

Crashed Thread: Unknown

Error Formulating Crash Report:

*** -[NSCFDictionary setObject:forKey:]: attempt to insert nil value (key: VMUSignaturePath)

0x917bffeb

0x95923e3b

0x917bfdcb

0x917bfe0a

0x90fa71f8

0x00093b31

0x000a39c1

0x000a3b17

0x000a0bab

0x000038f5

0x0000a992

0x00002ea4

0x000029f1

0x9088df4b

0x0000c254

0x90862055

0x90861f12

Backtrace not available

Unknown thread crashed with X86 Thread State (32-bit):

eax: 0xffff07a0 ebx: 0x94f9acc4 ecx: 0x00000038 edx: 0xffac59c0

edi: 0x00c3a670 esi: 0x00c3a074 ebp: 0xb0183dc8 esp: 0xb0183dc0

ss: 0x0000001f efl: 0x00010286 eip: 0xffff0f38 cs: 0x00000017

ds: 0x0000001f es: 0x0000001f fs: 0x0000001f gs: 0x00000037

cr2: 0x006ffff0

Binary images description not available