unrecognised SWI exception

[jitha]

Hi ,
    I am working on a multi tasking application to debug which I am using
ARM  AXD debugger .The application runs on an ARM9  board with ecos as the
OS. The image is an .axf(arm executable format) file.  The problem I am
facing is when i try doing the stepping, the debugger says
" Unrecognised SWI ".
Kindly let me know what could be the problem ASAP.
Thanks in advance.
 Regards,
       JPR