I suggest you install a new eclipse (so you will have 2 eclipses). I tried to add the Android and Blackberry plugin to my Eclipse Indigo (and I use a different workspace) and it gave me an error, and after that I could not create any Android / Blackberry project.
In any case, some people said that you can still use 1 eclipse for both plugins, but the Blackberry plugin must be installed first.
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