Please help, don't know how to solve--java.io.IOException: WritableName can't load class

Hello, guys, I am very new to hadoop. I was trying to read nutch data files using a script i found on http://wiki.apache.org/nutch/Getting_Started . And after 2 days of trying, I still cannot get it to work. now the error i got is "java.lang.RuntimeException: java.io.IOException: WritableName can'

Please help, don't know how to solve--java.io.IOException: WritableName can't load class

Hello, guys, I am very new to hadoop. I was trying to read nutch data files using a script i found on http://wiki.apache.org/nutch/Getting_Started . And after 2 days of trying, I still cannot get it to work. now the error i got is "java.lang.RuntimeException: java.io.IOException: WritableName can'