2.58 appcrash

Hi,
I want to continue my earlier project (made in 2.49) in 2.58 but I get this crashlog:

Problem Event Name: APPCRASH
Application Name: blender.exe
Application Version: 2.5.8.0
Application Timestamp: 4e0102f9
Fault Module Name: blender.exe
Fault Module Version: 2.5.8.0
Fault Module Timestamp: 4e0102f9
Exception Code: c0000005
Exception Offset: 0030e478
OS Version: 6.1.7600.2.0.0.256.48
Locale ID: 1033
Additional Information 1: 0a9e
Additional Information 2: 0a9e372d3b4ad19135b953a78882e789
Additional Information 3: 0a9e
Additional Information 4: 0a9e372d3b4ad19135b953a78882e789

after I want to delete (!) anything, or want to export the mesh.
:mad::eek: