invalid activator - eclipse

Question

I know there are other questions on the subject but I' ve tried them all and didn' t work for me. I want to write some output to excel files from my rcp plug in but it shows:
java.lang.NoClassDefFoundError: org/apache/poi/hssf/usermodel/HSSFWorkbook
So I do: plugin.xml->runtime tab-> add the poi jars in the classpath section.
But then when i try to run, it shows:
org.osgi.framework.BundleException: The activator spyros.getInfo.Activator for
bundle spyros.getInfo is invalid.
My questions:
Do i have to put the poi jars in a specific folder (example in META-INF folder) and then add them to classpath?
How can i fix the activator error?
My MANIFEST.MF
Manifest-Version: 1.0
Bundle-ManifestVersion: 2
Bundle-Name: GetInfo
Bundle-SymbolicName: spyros.getInfo; singleton:=true
Bundle-Version: 1.0.0.qualifier
Bundle-Activator: spyros.getInfo.Activator
Require-Bundle: org.eclipse.core.runtime,
org.eclipse.jdt.core;bundle-version="3.7.1",
org.eclipse.core.resources;bundle-version="3.7.100",
org.eclipse.ui,
org.eclipse.jdt.ui;bundle-version="3.7.1"
Bundle-ActivationPolicy: lazy
Bundle-RequiredExecutionEnvironment: JavaSE-1.6
Import-Package: org.apache.commons.collections
Bundle-ClassPath: lib/poi-3.8-20120326.jar,
lib/poi-examples-3.8-20120326.jar,
lib/poi-excelant-3.8-20120326.jar,
lib/poi-ooxml-3.8-20120326.jar,
lib/poi-ooxml-schemas-3.8-20120326.jar,
lib/poi-scratchpad-3.8-20120326.jar
My build properties
output.. = bin/
bin.includes = plugin.xml,\
META-INF/,\
icons/,\
lib/poi-3.8-20120326.jar,\
lib/poi-examples-3.8-20120326.jar,\
lib/poi-excelant-3.8-20120326.jar,\
lib/poi-ooxml-3.8-20120326.jar,\
lib/poi-ooxml-schemas-3.8-20120326.jar,\
lib/poi-scratchpad-3.8-20120326.jar
My plugin.xml
<?xml version="1.0" encoding="UTF-8"?>
<?eclipse version="3.4"?>
<plugin>
<extension
point="org.eclipse.ui.commands">
<command
defaultHandler="spyros.getInfo.handlers.GetInfo"
id="spyros.getInfo.commands.GetInfo"
name="GetInfo">
</command>
</extension>
<extension
point="org.eclipse.ui.menus">
<menuContribution
allPopups="false"
locationURI="menu:org.eclipse.ui.main.menu">
<menu
id="spyros.getInfo.commands.GetInfo"
label="My Info">
<command
commandId="spyros.getInfo.commands.GetInfo"
label="Get Info"
style="push"
tooltip="Get Info from methods">
</command>
</menu>
</menuContribution>
</extension>
</plugin>
I am so confused, but i am sure that stackoverflow community will help, because you are the best! Thanx in advance!

Answer 1

This is because of:
There has been a ClassNotFoundException trying to load the class in the first place, before it's even got to the start() method.
So for solve this problem:
You have to add . in to your class path see following image.
Add scr as source in your build and . in your bin.includes. See the image below: