Surefire fails with java.lang.ClassNotFoundException: org.apache.maven.surefire.Surefire

Surefire fails with exception:

org.apache.maven.surefire.booter.SurefireExecutionException: Unable to instantiate and execute Surefire; nested exception is java.lang.ClassNotFoundException: org.apache.maven.surefire.Surefire
java.lang.ClassNotFoundException: org.apache.maven.surefire.Surefire
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
at org.apache.maven.surefire.booter.IsolatedClassLoader.loadClass(IsolatedClassLoader.java:103)
at org.apache.maven.surefire.booter.SurefireBooter.runSuitesInProcess(SurefireBooter.java:281)
at org.apache.maven.surefire.booter.SurefireBooter.main(SurefireBooter.java:818)

This is probably due to the maven repository being located in a director containing a Swedish letter (C:\Documents and Settings\Pär\.m2\repository). When I changed the location of the repository the problem disappeared