Make two scripts sc1.avs and sc2.avs, each containing only "version()".
Drag sc1.avs on the graphedt window.
Then drag sc2.avs on the graphedt window.
Now graphedt may crash, if it does not crash yet, again drag sc1.avs on graphedt, now it probably will crash.
This crash occurs with avisynth 258 and later (but not with avisynth 257), so it may have to do with the COM interface.
The same behavior happens with (open source) graphstudio. (OS: XP professional SP3, bug seen on all tried PCs)