Java SE (Java Platform, Standard Edition)

I've created a program to test the JDBC MySQL Engine. When I compile it, everything works fine but when I try to run the program I get the following error:

Exception in thread "main" java.lang.NoClassDefFoundError: org/aspectj/lang/Signature
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at TestMySQL.main(TestMySQL.java:12)


The line 12 of TestMySQL.java is the following:
Class.forName("com.mysql.jdbc.Driver").newInstance();

I've also added the AspectJ .jar file location (which is the following: C:\Programmi\Java\jre1.5.0_04\lib\ext\aspectj-1.5.0M1.jar) to the CLASSPATH variable, but nothing worked.

How can I work around this problem??