Exception in thread "main" java.lang.UnsupportedClassVersionError: JVMCFRE003 bad major version; class=org/apache/commons/io/FilenameUtils, offset=6
    at java.lang.ClassLoader.defineClass(ClassLoader.java:275)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:69)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:540)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:451)
    at java.net.URLClassLoader.access$300(URLClassLoader.java:79)
    at java.net.URLClassLoader$ClassFinder.run(URLClassLoader.java:1038)
    at java.security.AccessController.doPrivileged(AccessController.java:284)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:429)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:660)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:358)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:626)
    at GenerateLoanReports.printCORRLoansFile(GenerateLoanReports.java:135)
    at GenerateLoanReports.main(GenerateLoanReports.java:69)

java version "1.6.0"
Java(TM) SE Runtime Environment (build pap6460sr9fp2-20110627_03(SR9 FP2))
IBM J9 VM (build 2.4, JRE 1.6.0 IBM J9 2.4 AIX ppc64-64 jvmap6460sr9-
20110624_85526 (JIT enabled, AOT enabled)
J9VM - 20110624_085526
JIT  - r9_20101028_17488ifx17
GC   - 20101027_AA)
JCL  - 20110530_01

1) File -> Project Structure -> Modules :: Sources (next to Paths and Dependencies)--> Language Level
2) File -> Settings -> Build, Execution, Deployment -> Compiler -> Java Compiler -> Project Bytecode version: 1.5
3) Project iml file - JDK 1_5
4) Maven compiler version - 1.5