Mobile Webdynpro on Blackberry gives http 401 unauthorized error

Hi,

We have developed a mobile webdynpro application for travel and expense and when it was accessed previously in blackberry it used to render the application as it is supposed to both in simulator and the blackberry device .But after we did a support pack upgrade it started giving a HTTP 401 unauthorized to view this application please try loading a different page error.We didnt change anything during the sp upgrade .Please can anyone help us with this as i have been trying for the solution since a week.

regards

swathi