Crash when adding Break Line

About half the time I add a "Break Line" to a measure the system crashes.
Windows 7 x64
4gb Ram + 4gb Readyboost
Here is the info from the Application Log
Log Name: Application
Source: Application Error
Date: 4/14/2010 2:59:50 PM
Event ID: 1000
Task Category: (100)
Level: Error
Keywords: Classic
User: N/A
Computer: Robs-Laptop
Description:
Faulting application name: mscore.exe, version: 0.0.0.0, time stamp: 0x4a82f024
Faulting module name: QtCore4.dll, version: 4.5.2.0, time stamp: 0x4a3f7c7e
Exception code: 0x40000015
Fault offset: 0x0000c956
Faulting process id: 0x1540
Faulting application start time: 0x01cadc1d2ca023dd
Faulting application path: C:\Program Files (x86)\MuseScore 0.9\bin\mscore.exe
Faulting module path: C:\Program Files (x86)\MuseScore 0.9\bin\QtCore4.dll
Report Id: 0bce953a-4811-11df-864c-0050f2e9a126
Event Xml:

1000
2
100
0x80000000000000

3974
Application
Robs-Laptop

mscore.exe
0.0.0.0
4a82f024
QtCore4.dll
4.5.2.0
4a3f7c7e
40000015
0000c956
1540
01cadc1d2ca023dd
C:\Program Files (x86)\MuseScore 0.9\bin\mscore.exe
C:\Program Files (x86)\MuseScore 0.9\bin\QtCore4.dll
0bce953a-4811-11df-864c-0050f2e9a126