There are few plugins in Nutch that need to be ported from 1.x to 2.x. Due to this reasons, the below plugins give errors when building with eclipse or when using them during the crawls.
1. Feed 2. Parse-swf 3. Parse-zip 4. Parse-ext
If you are trying to build Nutch 2.x with Eclipse, please do not add the above plugins in the build path if you are following the tutorial at http://wiki.apache.org/nutch/RunNutchInEclipse#preview.