Email problem with my PC browser(s)

Hello,

As of yesterday, I am unable to open my email from Firefox or Internet Explorer. I get as far as the login and password and then I received an internal error message (see below)

HTTP Status 500 -

type Exception report

message

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

exception

org.apache.jasper.JasperException: java.lang.NullPointerException
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:486)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:416)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
com.laszlosystems.webtop.core.transport.servlet.RequestLoggerFilter.doFilter(RequestLoggerFilter.java:96)
com.laszlosystems.webtop.core.transport.servlet.RequestCharacterEncodingFilter.doFilter(RequestCharacterEncodingFilter.java:129)

root cause

java.lang.NullPointerException

note The full stack trace of the root cause is available in the Apache Tomcat/6.0.18 logs.
Apache Tomcat/6.0.18


What is really strange is that I suddenly have Safari on my PC, and I can get email through that browser! No one seems to knows what's going on. HELP please!