Blender 2.49b Python Thread Safe

Im trying to access mesh data from within another thread in python. It work most of the time but every now and then I get a Bus Error or Segmentation Fault and Blender just quit. Is there a way to be able to implement a mechanism (using mutex or something, if this is not already provided, although I can’t seems to find anything relevant on google, and mutex doesn’t seems to work) to insure that the mesh data information can be accessed safely?

TIA