Error deploying a project on Tomcat

Hi,

I developed a web application on my computer using Eclipse and Tomcat. The app runs fine and I wanna now deploy it on a different machine.
So I installed tomcat and it's running fine with the basic configuration.

In eclipse I said export the dynamic web project as WAR file and I put it into tomcat webapps directory.
But as soon as I start the server now it gives me the following error:

SEVERE: ContainerBase.addChild: start:
org.apache.catalina.LifecycleException: Failed to start component [StandardEngin
e[Catalina].StandardHost[localhost].StandardContext[/IRSimWebApp]]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
        at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase
.java:901)
        at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:87
7)
        at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:633)

at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:977)

at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:
1655)
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
        at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
        at java.util.concurrent.FutureTask.run(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.IllegalArgumentException: The servlets named [addTreeServle
t] and [org.sven.addTreeServlet] are both mapped to the url-pattern [/addTreeSer
vlet] which is not permitted
        at org.apache.catalina.deploy.WebXml.addServletMapping(WebXml.java:335)
        at org.apache.catalina.startup.ContextConfig.processAnnotationWebServlet
(ContextConfig.java:2412)
        at org.apache.catalina.startup.ContextConfig.processAnnotationsStream(Co
ntextConfig.java:2125)
        at org.apache.catalina.startup.ContextConfig.processAnnotationsFile(Cont
extConfig.java:2080)
        at org.apache.catalina.startup.ContextConfig.processAnnotationsFile(Cont
extConfig.java:2073)
        at org.apache.catalina.startup.ContextConfig.processAnnotationsFile(Cont
extConfig.java:2073)
        at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.jav
a:1300)
        at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfi
g.java:878)
        at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfi
g.java:369)
        at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(Lifecycl
eSupport.java:119)
        at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBa
se.java:90)
        at org.apache.catalina.core.StandardContext.startInternal(StandardContex
t.java:5179)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
        ... 11 more

Feb 25, 2013 12:08:22 PM org.apache.catalina.startup.HostConfig deployWAR
SEVERE: Error deploying web application archive C:\apache-tomcat-7.0.37\webapps\
IRSimWebApp.war
java.lang.IllegalStateException: ContainerBase.addChild: start: org.apache.catal
ina.LifecycleException: Failed to start component [StandardEngine[Catalina].Stan
dardHost[localhost].StandardContext[/IRSimWebApp]]
        at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase
.java:904)
        at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:87
7)
        at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:633)

at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:977)

at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:
1655)
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
        at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
        at java.util.concurrent.FutureTask.run(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)

Any ideas on that?
I use tomcat 7.0.37 and Java 7

edit: it looks like it directs to an error in the web.xml.. but I can't seem to find any:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>IRSimWebApp</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  
  <servlet>
    <servlet-name>addTreeServlet</servlet-name>
    <servlet-class>addTreeServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>addTreeServlet</servlet-name>
    <url-pattern>/addTreeServlet</url-pattern>
  </servlet-mapping>
  
   <servlet>
    <servlet-name>UploadServlet</servlet-name>
    <servlet-class>UploadServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>UploadServlet</servlet-name>
    <url-pattern>/UploadServlet</url-pattern>
  </servlet-mapping>
  
</web-app>

Welcome to the JavaRanch, Leo! You have in fact made 2 separate definitions for the addTreeServlet. They're both wrong, also. The servlet definition needs to be supplied with the fully-qualified classname of the servlet, not its simple name. So, in other words:

For example.