Unable to build AS - svn command failed

When trying to build the AS from source by running ./build.sh (as described in README.txt), I get this error:

[INFO] Checking for local modifications: skipped.
[INFO] Updating project files from SCM: skipped.
[INFO] Executing: /bin/sh -c cd /opt/mmalina/jboss-6.0.0.20100215-M2-src/main && svn --non-interactive info
[INFO] Working directory: /opt/mmalina/jboss-6.0.0.20100215-M2-src/main
Provider message:
The svn command failed.
Command output:
svn: '.' is not a working copy

[INFO] ------------------------------------------------------------------------
[ERROR] BUILD ERROR
[INFO] ------------------------------------------------------------------------
[INFO] Cannot get the revision information from the scm repository :
Error!

[INFO] ------------------------------------------------------------------------
[INFO] For more information, run Maven with the -e switch
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 53 seconds
[INFO] Finished at: Mon Feb 15 08:38:32 EST 2010
[INFO] Final Memory: 84M/501M
[INFO] ------------------------------------------------------------------------