Problem creating an image from a remote url

I am creating a servlet which does the following:
1. retrieves an image from a remote url
2. resizes the image
3. sends the image to the client.

The servlet works fine when I run it on my PC, but when I run it on the server, it doesn't. Here's the problematic code

private Image getRemoteImage(String imageUrl) throws Exception {
        System.err.println("in getRemoteImage()");
        if (!imageUrl.startsWith("http://")) imageUrl = "http://" + imageUrl;
        URL u = new URL(imageUrl);
        System.err.println("imageUrl: " + imageUrl);
        HttpURLConnection huc = (HttpURLConnection) u.openConnection();
        huc.setRequestMethod("GET");
        System.err.println("connecting...");
        huc.connect();
        System.err.println("Getting DataInputStream...");
        DataInputStream in = new DataInputStream(u.openStream());
        //DataInputStream in = new DataInputStream(huc.getInputStream()); 
        System.err.println("...got");
        int numBytes = huc.getContentLength(); //1063
        System.err.println("numBytes: " + numBytes);
        byte[] imageBytes = new byte[numBytes];
        System.err.println("reading fully...");
        in.readFully(imageBytes);
        System.err.println("...read");
        in.close();
        System.err.println("creating imageIcon");
        ImageIcon imageIcon = new ImageIcon(imageBytes);  //   <-- problem here
        System.err.println("** THIS LINE IS NOT REACHED **");
        System.err.println("creating image");
        Image image = imageIcon.getImage();
        System.err.println("returning image");
        return image;
    }

When I access the servlet with FF, the browser reports:
The image �<my servlet url>� cannot be displayed, because it contains errors.

When I access the servlet with IE, I get:
Apache Tomcat/4.0.3 - HTTP Status 500 - Internal Server Error

--------------------------------------------------------------------------------

type Exception report

message Internal Server Error

description The server encountered an internal error (Internal Server Error) that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: Servlet execution threw an exception
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:243)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:190)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2343)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)
at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:170)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:170)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:468)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at org.apache.ajp.tomcat4.Ajp13Processor.process(Ajp13Processor.java:429)
at org.apache.ajp.tomcat4.Ajp13Processor.run(Ajp13Processor.java:495)
at java.lang.Thread.run(Thread.java:534)

root cause

java.lang.NoClassDefFoundError
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:141)
at java.awt.Toolkit$2.run(Toolkit.java:748)
at java.security.AccessController.doPrivileged(Native Method)
at java.awt.Toolkit.getDefaultToolkit(Toolkit.java:739)
at javax.swing.ImageIcon.(ImageIcon.java:205)
at myservlets.GetImage.getRemoteImage(GetImage.java:283)
at myservlets.GetImage.processRequest(GetImage.java:73)
at myservlets.GetImage.doGet(GetImage.java:394)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:243)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:190)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2343)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)
at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:170)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:170)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:468)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at org.apache.ajp.tomcat4.Ajp13Processor.process(Ajp13Processor.java:429)
at org.apache.ajp.tomcat4.Ajp13Processor.run(Ajp13Processor.java:495)
at java.lang.Thread.run(Thread.java:534)

Any ideas?

Cheers,
James