getting error when installing new-doc plugin in grails - grails

Question

I am getting failed download error when trying to install new-doc plugin. The error message I get looks like:
==== http://repo.grails.org/grails/libs-releases-local: tried
http://repo.grails.org/grails/libs-releases-local/net/sf/json-lib/json
-lib/2.4/json-lib-2.4.jar
::::::::::::::::::::::::::::::::::::::::::::::
:: FAILED DOWNLOADS ::
:: ^ see resolution messages for details ^ ::
::::::::::::::::::::::::::::::::::::::::::::::
:: net.sf.json-lib#json-lib;2.4!json-lib.jar
::::::::::::::::::::::::::::::::::::::::::::::
| Error Failed to resolve dependencies (Set log level to 'warn' in BuildConfig.groovy for more information):
- net.sf.json-lib:json-lib:2.4
My BuildConfig.groovy looks like:
grails.servlet.version = "3.0" // Change depending on target container compliance (2.5 or 3.0)
grails.project.class.dir = "target/classes"
grails.project.test.class.dir = "target/test-classes"
grails.project.test.reports.dir = "target/test-reports"
grails.project.plugins.dir = "plugins"
grails.project.war.file = "target/${appName}.war"
grails.project.dependency.resolution = {
// inherit Grails' default dependencies
inherits("global") {
// uncomment to disable ehcache
// excludes 'ehcache'
}
log "warn" // log level of Ivy resolver, either 'error', 'warn', 'info', 'debug' or 'verbose'
repositories {
grailsPlugins()
grailsHome()
grailsCentral()
// uncomment the below to enable remote dependency resolution
// from public Maven repositories
//mavenLocal()
mavenCentral()
//mavenRepo "http://snapshots.repository.codehaus.org"
//mavenRepo "http://repository.codehaus.org"
//mavenRepo "http://download.java.net/maven/2/"
//mavenRepo "http://repository.jboss.com/maven2/"
}
dependencies {
// specify dependencies here under either 'build', 'compile', 'runtime', 'test' or 'provided' scopes eg.
compile 'org.apache.poi:poi:3.9'
compile 'org.apache.poi:poi-ooxml:3.9'
compile 'com.google.guava:guava:12.0'
}
plugins {
compile ":new-doc:0.3.2"
}
}
I am fairly new to groovy/grails so I am not sure what should I do next to resolve this issue. Or can anyone suggest me any other code documentation plugin for grails?
Thanks,
Dee
NOTE
When I ran "grails doc" it generated all the documentation code in target/docs folder. It has index.html page which I thought would list all the api functions, but it didn't have any information on the api documents there - so I wrongly concluded that grails doc was not generating the API documentation. I should have looked into target/docs/gapi folder instead to get the generated API documents for grails. I apologize for my noob problem, and not being able to see the solution that was right there in front of me. Thanks.