Objects disappear in 2.49

Hello everyone,

I’m using Blender 2.49b and have annoying issue on all my projects so far - missing objects after I reopen file… This happens time to time.
Some of my meshes, cameras, empties, armatures - gone forever! Can’t find them neither in the Outliner, and file size became smaller!
This forces me to keep long list of versions, constantly checking if they were saved properly and all objects in their places.
Please help to figure out what may I do wrong… I have 2 machines with Win7x64 and WinXPx32, both systems seems to be affected equally.