JUnit issues

[aca10mpr]

Hello. I've added the JUnit jar to my classpath, and it can find and run tests alright using the command window, but when I try and compile a test I know works, it can't seem to find anything to do with JUnit. I get the following error for every test class. Tested it on another computer and it works, but not on mine. Any ideas?

EstateAgentTest.java:25: incompatible types
found : Test
required: java.lang.annotation.Annotation
@Test public void rentable1() {
Thanks a lot.