Building API Manager from source fails - wso2

Question

I'm trying to build the API Manager from source according to the documentation at http://docs.wso2.org/wiki/display/AM130/Obtaining+the+Product#ObtainingtheProduct-source
I did svn checkout http://svn.wso2.org/repos/wso2/carbon/platform/tags/4.0.3/products/apimgt/1.2.0 wso2carbon
Then I did "mvn clean install -Dproduct=apimgt"
I'm using maven 3 and Java 6. I'm getting the error below; any ideas on what's wrong and how I can build the source?...
[ERROR] Failed to execute goal org.wso2.maven:carbon-p2-plugin:1.5:p2-profile-ge
n (3-p2-profile-generation) on project am-p2-profile: P2 publisher return code w
as 13 -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal o
rg.wso2.maven:carbon-p2-plugin:1.5:p2-profile-gen (3-p2-profile-generation) on p
roject am-p2-profile: P2 publisher return code was 13
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor
.java:217)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor
.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor
.java:145)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProje
ct(LifecycleModuleBuilder.java:84)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProje
ct(LifecycleModuleBuilder.java:59)
at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBu
ild(LifecycleStarter.java:183)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(Lifecycl
eStarter.java:161)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:320)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.
java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Laun
cher.java:290)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.jav
a:230)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(La
uncher.java:409)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:
352)
Caused by: org.apache.maven.plugin.MojoExecutionException: P2 publisher return c
ode was 13
at org.wso2.maven.p2.ProfileGenMojo.execute(ProfileGenMojo.java:171)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(Default
BuildPluginManager.java:101)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor
.java:209)
... 19 more
Caused by: org.apache.maven.plugin.MojoFailureException: P2 publisher return cod
e was 13
at org.wso2.maven.p2.ProfileGenMojo.installFeatures(ProfileGenMojo.java:
213)
at org.wso2.maven.p2.ProfileGenMojo.execute(ProfileGenMojo.java:164)
... 21 more