Images and ServletExec - container for JSP

I am using the grid control, which has a number of images loaded, 4 to be exact. What i noticed is the first time ..grid loads just fine with all images. Once i click on the column to do the sorting, the sort works, but my images disappear. Click on the sort column again, and JSP container throws a exception and nothing works after that. In other words, it appears to halt the Servlet contaioner, and i need to restart the server..which i cam running locally

Here is a snippet of what the Servlet container logs reports..

/styles/grid.png
/styles/grid.png
/styles/grid.png
/styles/grid.png
/styles/grid.png
/styles/grid.png
/styles/grid.png
/styles/grid.png
/styles/grid.png
/styles/grid.png
/styles/grid.png
/styles/grid.png
/styles/grid.png
/styles/grid.png
/styles/unread.ico
/styles/grid.png
/styles/grid.png
/styles/grid.png
/styles/unread.ico
/styles/grid.png
/styles/unread.ico
/styles/unread.ico
/styles/unread.ico
/styles/unread.ico
/styles/unread.ico
/styles/grid.png
/styles/grid.png
/styles/unread.ico
/styles/unread.ico
java.lang.NullPointerException
at com.newatlanta.sedebugger.Responder.run(Responder.java)
/styles/grid.png
/styles/grid.png
java.lang.NullPointerException
at com.newatlanta.sedebugger.Responder.run(Responder.java)
java.lang.NullPointerException
at com.newatlanta.sedebugger.Responder.run(Responder.java)

Any ideas here? Has anyone run into this issue..please advise