Which plugin did you add? Did you write it yourself? If so, are you doing any kind of memory management (e.g. qmalloc(), qfree())?
If so, I would look there first. If it is someone else's plugin, sans source, you are likely going to be somewhat out of luck here as there can be any number of problems associated with an access violation.
If the problem persists, and you are a licensed IDA Pro user, you probably should contact Datarescue with the details of the bug and they will be extremely prompt in their response.
If it is an openly available plugin, you are probably better off to contact the plugin's author as SDK support is only available from DataRescue for a fee. If it is a common plugin, perhaps it is something that people here have used, but you will need to provide more information about your problem.
Chris
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