While running a report, i face following error

Fatal error:rep.data index 1001 out of dimension[2] 1000
Fatal error can not continue
But same report working fine earlier.
Can you tel me what is the problem.

Are you sure nobody changed the session script or report data? Maybe dimensions do not match between report and session. Can you put it in debug mode and see exactly what and where the error is occuring?

Maybe an counter exceeds its range ... we had this with an email soultion ... every messages had an id ... the id exceeds its range after some weeks resulting in errors using the wrong data type for that.