When installing a new version
The current releases are still developmental snapshots, so there are continual api changes. When installing a new version of Editra if you start getting crashes related to Plugins that you have installed from a previous version always do the following.
1) Open the PluginManager
2) Look for updates to your existing plugins in the Downloads Tab
3) Install any newer versions of the plugins you use as they may have compatibility changes to adapt to the new release of Editra.
As things get closer to a stable release cycle the PluginManager and Plugin framework will automatically manage these kind of things and provide notifications of when updates are available.
The plugin I hear about the most is the Calculator plugin. The 0.5 release of the plugin is no longer compatible with current releases so use the plugin manager to update it to 0.6 which is. Was quite surprised to see how many people are using that example plugin.