crystal reports 9 error on server 2003 R2 SP 2

Crystal reports 9

server 2003 R2 , SP 2 Server

Error is

Microsoft VBScript runtime error '800a01a8'

Object required: '[undefined]'

/mcis/reports/reportViewer.asp, line 1529

and the code at this line is

On Error Goto 0

  session("oRpt").DiscardSavedData -- this is where the error is coming.

this application is running on classic ASP.

it was working fine until this morning, all of sudden this error started showing up and could not find any solution for this issue, this is little bit urgent, I really appreciate if some one can respond, this is stopping users work since morning.

Thank you